Friday, June 17, 2011

Nonvolatile BIOS memory - CMOS

Nonvolatile BIOS memory - CMOS

CMOS Battery in a Pico ITX motherboard

Non-volatile BIOS memory refers to the memory on a personal computer motherboard containing BIOS settings and sometimes the code used to initialize the computer and load the operating system. The non-volatile memory was historically called CMOS RAM or just CMOS because it traditionally used a low-power CMOS memory chip (the Motorola MC146818, or one of its higher-capacity clones), which was powered by a small battery when the system power was off. The term remains in wide use in this context, but has also grown into a misnomer. The non-volatile BIOS storage in contemporary computers might be in an EEPROM or flash memory chip and not in a volatile CMOS RAM. In these cases, the battery back-up is meant to keep the RTC chip synchronized. The NVRAM normally has a storage capacity of 512 Bytes, which is enough for all BIOS-settings.

CMOS mismatch

CMOS mismatch errors typically occur if the computer's power-on self-test program:

  1. Finds a device that is not recorded in the CMOS.
  2. Does not find a device that is recorded in the CMOS.
  3. Finds a device that has different settings than those recorded for it in CMOS.
  4. Detects a CMOS checksum error. [1] [2]

CMOS battery

Type CR2032 button cell, most common CMOS battery.

The memory and real-time clock are generally powered by a CR2032 lithium coin cell. These cells last two to ten years, depending on the type of motherboard, ambient temperature and the time that the system is powered off, while other common cell types can last significantly longer or shorter periods, such as the CR2016 which will generally last about 40% as long. Higher temperatures and longer power-off time will shorten cell life. When replacing the cell, the system time and CMOS BIOS settings may revert to default values. This may be avoided by replacing the cell with the power supply master switch on. On ATX motherboards, this will supply 5V standby power to the motherboard even if it is apparently "switched off", and keep the CMOS memory energized.

Resetting the CMOS settings

To access the BIOS setup when the machine fails to operate, occasionally a drastic move is required. In older computers with battery-backed RAM, removal of the battery and short circuiting the battery input terminals for a while did the job; in some more modern machines this move only resets the RTC. Some motherboards offer a CMOS-reset jumper or a reset button. In yet other cases, the EEPROM chip has to be desoldered and the data in it manually edited using a programmer. Sometimes it is enough to ground the CLK or DTA line of the I²C bus of the EEPROM at the right moment during boot, this requires some precise soldering on SMD parts. If the machine lets you boot but does not want to let you into the BIOS setup, one possible recovery is to deliberately "damage" the CMOS checksum by doing direct port writes using debug.exe, corrupting some bytes of the checksum-protected area of the CMOS RAM; at the next boot, the computer typically resets its setting to factory defaults.

AwardBIOS Error Messages

When a personal computer is first turned on, the BIOS tests and configures various components to ensure that they are operating correctly. This operation is called POST (power-on self test). If the BIOS detects any problems during this testing phase, it will attempt to continue to start the computer. However, if the problems are severe, the BIOS may be forced to halt the system.

When an error is detected, the BIOS program will:

§ Display the error to the screen, if possible.

§ Generate a POST beep code using the computer's internal speaker if it cannot access the display adaptor.

§ Provide a POST code output that can be read using a special hardware tool.

Beep Codes

§ The only AwardBIOS beep code indicates that a video error has occurred and the BIOS cannot initialize the video screen to display any additional information. This beep code consists of a single long beep followed by two short beeps. Any other beeps are probably a RAM (Random Access Memory) problems.

Screen Error Messages

The following messages are examples of messages including errors detected by the BIOS during POST and a description of what they mean and/or what you may do to correct the error.

BIOS ROM checksum error - System halted

The checksum of the BIOS code in the BIOS chip is incorrect, indicating the BIOS code may have become corrupt. Contact your system dealer to replace the BIOS.

CMOS battery failed

The CMOS battery is no longer functional. Contact your system dealer for a replacement battery.

CMOS checksum error - Defaults loaded

Checksum of CMOS is incorrect, so the system loads the default equipment configuration. A checksum error may indicate that CMOS has become corrupt. This error may have been caused by a weak battery. Check the battery and replace if necessary.

CPU at nnnn

Displays the running speed of the CPU.

Display switch is set incorrectly

The display switch on the motherboard can be set to either monochrome or color. This message indicates the switch is set to a different setting than indicated in Setup. Determine which setting is correct, and then either turn off the system and change the jumper, or enter Setup and change the VIDEO selection.

Press ESC to skip memory test

The user may press Esc to skip the full memory test.

Floppy disk(s) fail

Cannot find or initialize the floppy drive controller or the drive. Make sure the controller is installed correctly. If no floppy drives are installed, be sure the Diskette Drive selection in Setup is set to NONE or AUTO.

HARD DISK initializing
Please wait a moment

Some hard drives require extra time to initialize.

HARD DISK INSTALL FAILURE

Cannot find or initialize the hard drive controller or the drive. Make sure the controller is installed correctly. If no hard drives are installed, be sure the Hard Drive selection in Setup is set to NONE.

Hard disk(s) diagnosis fail

The system may run specific disk diagnostic routines. This message appears if one or more hard disks return an error when the diagnostics run.

Keyboard error or no keyboard present

Cannot initialize the keyboard. Make sure the keyboard is attached correctly and no keys are pressed during POST. To purposely configure the system without a keyboard, set the error halt condition in Setup to HALT ON ALL, BUT KEYBOARD. The BIOS then ignores the missing keyboard during POST.

Keyboard is locked out - Unlock the key

This message usually indicates that one or more keys have been pressed during the keyboard tests. Be sure no objects are resting on the keyboard.

Memory Test:

This message displays during a full memory test, counting down the memory areas being tested.

Memory test fail

If POST detects an error during memory testing, additional information appears giving specifics about the type and location of the memory error.

Override enabled - Defaults loaded

If the system cannot boot using the current CMOS configuration, the BIOS can override the current configuration with a set of BIOS defaults designed for the most stable, minimal-performance system operations.

Press TAB to show POST screen

System OEMs may replace the Phoenix Technologies' AwardBIOS POST display with their own proprietary display. Including this message in the OEM display permits the operator to switch between the OEM display and the default POST display.

Primary master hard disk fail

POST detects an error in the primary master IDE hard drive.

Primary slave hard disk fail

POST detects an error in the secondary master IDE hard drive.

Resuming from disk, Press TAB to show POST screen

Phoenix Technologies offers a save-to-disk feature for notebook computers. This message may appear when the operator re-starts the system after a save-to-disk shut-down. See the Press Tab & message above for a description of this feature.

Secondary master hard disk fail

POST detects an error in the primary slave IDE hard drive.

Secondary slave hard disk fail

POST detects an error in the secondary slave IDE hard drive.

Index of Setup Fields for AwardBIOS

This page lists Setup fields found in the following Setup screens:

§ Standard CMOS

§ BIOS Features

§ Chipset Features

§ Power Management

§ PNP/PCI Configuration

§ Integrated Peripherals

Numeric

16 Bit I/O Recovery Time

See 8/16 Bit I/O Recovery Time, below.

16 Bit ISA I/O Command WS

Your system quite possibly has much higher performance than some of your input/output (I/O) devices. This means that unless the system is instructed to allow more time, more wait states, for devices to respond, it might think the device has malfunctioned and stop its request for I/O. If all your I/O devices are capable, then disabling this setting could result in greater throughput. Otherwise, data could be lost.

16 Bit ISA Mem Command WS

When memory is accessed on the ISA bus, the system must allow for the relatively slow speed of the ISA bus. This setting allows you to match the speed of device memory located on the ISA bus with the system ability to read/write to that memory.

1st/2nd Fast DMA Channel

Select up to two DMA channels for Type F DMA, if supported by the I/O peripheral using the DMA channel.

1st/2nd/3rd/4th Available IRQ

If an installed PCI device requires interrupt service, you may manually select an unused interrupt line for PCI IRQs. NA indicates the interrupt is assigned to an ISA bus device and is not available to any PCI slot.

2 Bank PBSRAM

For PBSRAMs, 3-1-1-1 timing is available for both read and write transactions at 66 or 75 MHz. VP2

2nd Channel IDE

If you install an add-in IDE interface as the second IDE channel, select Disabled to avoid a conflict with the on-chip second IDE channel.

8/16 Bit I/O Recovery Time

The I/O recovery mechanism adds bus clock cycles between PCI-originated I/O cycles to the ISA bus. This delay takes place because the PCI bus is much faster than the ISA bus.

These two fields let you add recovery time (in bus clock cycles) for 16-bit and 8-bit I/O.

A

ACPI I/O Device Node

Selecting Enabled enables ACPI device node reporting from the BIOS to the operating system. VP2

AGP Aperture Size (MB)

Select the size of the Accelerated Graphics Port (AGP) aperture. The aperture is a portion of the PCI memory address range dedicated for graphics memory address space. Host cycles that hit the aperture range are forwarded to the AGP without any translation.

ALE During Bus Conversion

Depending on system speed, you can select a Single or a Multiple ALE signal during a bus conversion cycle.

APM BIOS

Select Enabled to turn on the BIOS power-management features.

Asysc. SRAM Read WS

Select the correct cycle timing combination for the system board design and SRAM specifications.

Asysc. SRAM Write WS

Select the correct cycle timing combination for the system board design and SRAM specifications.

AT Clock Option

The system board designer selects whether the AT bus clock is tightly synchronized with the CPU clock or is asynchronous.

AT-BUS Clock

The chipset generates the ISA bus clock (ATCLK) from an internal division of PCICLK. You can set the speed of the AT bus in terms of a fraction of the CPU clock speed, or at the fixed speed of 7.16 MHz.

Audio DMA Select

Select a DMA channel for the audio port.

Audio I/O Base Address

Select a base I/O address for the audio port.

Audio IRQ Select

Select an interrupt for the audio port.

Auto Clock Control

If APM is not enabled or not present in your system, the BIOS manages the CPU clock when this field is Enabled in the same way APM power management would manage the clock.

Auto Configuration

Auto Configuration selects predetermined optimal values of chipset parameters. When Disabled, chipset parameters revert to setup information stored in CMOS. Many fields in this screen are not available when Auto Configuration is Enabled.

Auto Detect DIMM/PCI Clk

To reduce the occurrence of electromagnetic interference (EMI), the BIOS detects the presence or absence of components in DIMM and PCI slots and turns off system clock generator pulses to empty slots.

Auto Suspend Timeout

After the selected period of system inactivity, the system automatically enters Suspend mode.

B

Back to Back I/O Delay

Select Enabled to insert three ATCLK signals in back-to-back AT bus I/O cycles.

Bank 0/1 DRAM Type

The value in this field is set by the system board manufacturer, depending on whether the board has paged DRAMs or EDO (extended data output) DRAMs.

BIOS PM on AC

If you wish the BIOS power-management features to remain active when the system is connected to an external power source, set to On.

BIOS PM Timers

After the selected period of inactivity for each subsystem (video, hard drive, peripherals), that subsystem enters Standby mode.

Boot From LAN First

When Enabled, the BIOS attempts to boot from a LAN boot image before it attempts to boot from a local storage device.

Boot Sequence

The original IBM PCs loaded the DOS operating system from drive A (floppy disk), so IBM PC-compatible systems are designed to search for an operating system first on drive A, and then on drive C (hard disk). However, modern computers usually load the operating system from the hard drive, and may even load it from a CD-ROM drive.

Boot Up Floppy Seek

When Enabled, the BIOS tests (seeks) floppy drives to determine whether they have 40 or 80 tracks. Only 360-KB floppy drives have 40 tracks; drives with 720 KB, 1.2 MB, and 1.44 MB capacity all have 80 tracks. Because very few modern PCs have 40-track floppy drives, we recommend that you set this field to Disabled to save time.

Boot Up NumLock Status

Toggle between On or Off to control the state of the NumLock key when the system boots. When toggled On, the numeric keypad generates numbers instead of controlling cursor operations.

Boot Up System Speed

Select High to boot at the default CPU speed; select Low to boot at the speed of the AT bus. Some add-in peripherals or old software (such as old games) may require a slow CPU speed. The default setting is High.

Burst Write Combining

When this option is Enabled, the chipset assembles long PCI bursts from the data held in these buffers.

Byte Merge

This field controls the byte-merge feature for frame buffer cycles. When Enabled, the controller checks the eight CPU Byte Enable signals to determine if data bytes read from the PCI bus by the CPU can be merged.

Byte Merge Support

Byte merging holds 8- or 16-bit data sent from the CPU to the PCI bus in a buffer where it is accumulated, or merged, into 32-bit data for faster performance. The chipset then writes the data in the buffer to the PCI bus when appropriate. PCI Pipeline and Pipelining combine PCI or CPU pipelining with byte merging. Byte merging is used to enhance video performance.

C

Cache Read Burst

These SRAM timing numbers are the pattern of cycles the CPU uses to read data from the cache. The system board designer must select the proper combination, depending on the cache size and access speed of the cache SRAMs. Do not reset this option from its default.

Cache Read Wait States

Select the number of wait states for the cache output enable signals. When 0 WS is selected, CROEA# and CROEB# are active for 2 CPU clocks; for 1 WS, CROEA# and CROEB# are active for 3 CPU clocks. The actual number of clocks that CROE# remains active may be longer. The number is automatically adjusted during L2 cache write-back-to-DRAM cycles to synchronize with the DRAM controller.

Cache Timing

For a secondary cache of one bank, select Faster. For a secondary cache of two banks, select Fastest. VP2

Cache Write Burst

Sets the precise timing used during burst writes to the cache.

Cache Write Wait State

The system board designer may elect to insert a wait state into the cache write cycle, if necessary.

CAS Address Hold Time

Select the number of cycles it takes to change the CAS address after CAS has been initiated (asserted) aimed at a target address (location) in DRAM.

CAS Low Time for Write/Read

The number of clocks cycles the CAS signal is pulled low for DRAM writes and reads depends on the DRAM timing. Do not reset this field from the default value specified by the system designer.

CAS# Precharge Time

Select the number of CPU clocks allocated for the CAS# signal to accumulate its charge before the DRAM is refreshed. If insufficient time is allowed, refresh may be incomplete and data lost.

CAS Pulse Width

The system designer must set the duration of a CAS signal pulse (in timer ticks).

Chipset NA# Asserted

Selecting Enabled permits pipelining, in which the chipset signals the CPU for a new memory address before all data transfers for the current cycle are complete, resulting in faster performance.

Chipset Special Features

When disabled, the chipset behaves as if it were the earlier Intel 82430FX chipset.

CPU Addr. Pipelining

Pipelining allows the system controller to signal the CPU for a new memory address even before all data transfers for the current cycle are complete, resulting in increased throughput.

CPU Burst Write Assembly

The chipset maintains four posted write buffers. When this option is enabled, the chipset is allowed to assemble long PCI bursts from the data held in these buffers.

CPU Core Voltage

Set this field to match the voltage of the installed CPU, or set to Auto to permit the BIOS to autodetect the voltage. End users should not change the value in this field unless they replace the CPU with one of a different voltage. VP2

CPU fan on temp high

When the CPU temperature reaches a preset limit, the CPU fan turns on.

CPU Host/PCI Clock

Select Default or select a timing combination for the CPU and the PCI bus. When set to Default, the BIOS uses the actual CPU and PCI bus clock values.

CPU Internal Cache /External Cache

Cache memory is additional memory that is much faster than conventional DRAM (system memory). CPUs from 486-type on up contain internal cache memory, and most, but not all, modern PCs have additional (external) cache memory. When the CPU requests data, the system transfers the requested data from the main DRAM into cache memory, for even faster access by the CPU.

CPU Line Read

This field lets you Enable or Disable full CPU line reads.

CPU L2 Cache ECC Checking

When you select Enabled, memory checking is enable when the external cache contains ECC SRAMs.

CPU Line Read Multiple

A line read means that the CPU is reading a full cache line. When a cache line is full it holds 32 bytes (eight DWORDS) of data. Because the line is full, the system knows exactly how much data it will be reading and it doesn't need to wait for an end-of-data signal, freeing it to do other things.

When this item is Enabled, the system is allowed to read more than one full cache line at a time.

CPU Line Read Prefetch

See the field below. When this item is Enabled, the system is allowed to prefetch the next read instruction and initiate the next process.

CPU Read Multiple Prefetch

A prefetch occurs during a process (e.g., reading from the PCI or memory) when the chipset "peeks" at the next instruction and actually begins the next read instruction. This chipset has four read lines. A multiple prefetch means that the chipset has the capacity to initiate more than one prefetch during a process.

CPU to DRAM Page Mode

When Disabled, the memory controller closes the DRAM page after a DRAM access. When Enabled, the DRAM page remains open until the next access.

CPU to PCI Buffer

When this field is Enabled, writes from the CPU to the PCI bus are buffered, to compensate for the speed differences between the CPU and the PCI bus. When Disabled, the writes are not buffered and the CPU must wait until the write is complete before starting another write cycle.

CPU-To-PCI Burst Mem. WR.

When this option is enabled, the chipset is allowed to assemble long PCI bursts from the data held in its buffers. SIS5597

CPU to PCI Byte Merge

Byte merging permits merging of the data in consecutive CPU-to-PCI byte/word writes with the same dword address, into the same posted write buffer location. The merged collection of bytes is then sent over the PCI Bus as a single dword. Byte merging is performed in the compatible VGA range only (0A0000-0BFFFF).

CPU-To-PCI IDE Posting

Select Enabled to post write cycles from the CPU to the PCI IDE interface. IDE accesses are posted in the CPU to PCI buffers, for cycle optimization.

CPU to PCI POST/BURST

Data from the CPU to the PCI bus can be posted (buffered by the controller) and/or burst. These are the methods:

POST/CON.BURST

Posting and conservative bursting

POST/Agg.BURST

Posting and aggressive bursting

NONE/NONE

Neither posting nor bursting

POST/NONE

Posting but not bursting

CPU-To-PCI Write Buffer

When Enabled, the CPU can write up to four dwords of data to the PCI write buffer before the CPU must wait for the PCI bus cycles to finish. When Disabled, the CPU must wait after each write cycle until the PCI bus signals that it is ready to receive more data.

CPU-To-PCI Write Post

When this field is Enabled, writes from the CPU to the PCI bus are buffered, to compensate for the speed differences between the CPU and the PCI bus. When Disabled, the writes are not buffered and the CPU must wait until the write is complete before starting another write cycle.

CPU Warning Temperature

Select the combination of lower and upper limits for the CPU temperature. If the CPU temperature extends beyond either limit, any warning mechanism programmed into your system will be activated.

CPU/PCI Write Phase

Determines the number of clock signals between the address and data phases of the CPU-master-to-PCI-slave writes.

CPUFAN Off in Suspend

When Enabled, the CPU fan turns off during Suspend mode.

CRT Power Down

When Enabled, the CRT powers down when the system enters a Green mode.

CRT Sleep

Determines the manner in which the monitor is blanked.

Current CPU Temperature

This field displays the current CPU temperature, if your computer contains a monitoring system.

Current CPUFAN 1/2/3 Speed

These fields display the current speed of up to three CPU fans, if your computer contains a monitoring system.

Current System Temperature

This field displays the current system temperature, if your computer contains a monitoring system.

D

Date

The BIOS determines the day of the week from the other date information; this field is for information only.

Press the right or left arrow key to move to the desired field (date, month, year). Press the PgUp or PgDn key to increment the setting, or type the desired value into the field.

Day of Month Alarm

Select a date in the month. Select 0 (zero) if you prefer to set a weekly alarm. SIS5597

Daylight Saving

When enabled, this parameter adds one hour to the clock when daylight-saving time begins. It also subtracts one hour when standard time returns.

Delayed Transaction

The chipset has an embedded 32-bit posted write buffer to support delay transactions cycles. Select Enabled to support compliance with PCI specification version 2.1.

Dirty pin selection

When Combine is selected in the Tag/Dirty Implement field, you can choose whether the dirty data pin is I/O, for bidirectional input/output, or IN, for input only.

DMA Clock

This item allows you to set the speed of Direct Memory Access (DMA) at either equal to or one-half of the SYSCLK (system clock signal) speed. While speed is always desirable, choosing the higher setting may prove to be too fast for some components.

DMA n Assigned to

When resources are controlled manually, assign each system DMA channel as one of the following types:

Legacy ISA:

Devices compliant with the original PC AT bus specification, requiring a specific DMA channel

PCI/ISA PnP:

Devices compliant with the Plug and Play standard, whether designed for PCI or ISA bus architecture.

Doze Mode

After the selected period of system inactivity, the CPU clock runs at slower speed while all other devices still operate at full speed.

Doze Speed (div by)

Select a divisor to reduce the CPU speed during Doze mode to a fraction of the full CPU speed.

Doze Timer

After the selected period of system inactivity, the CPU clock runs at slower speed while all other devices still operate at full speed.

Doze Timer Select

Select the timeout period (period of system inactivity) after which the system enters Doze mode.

DRAM Auto Configuration

The system board designer must select the proper value for this field, according to the specifications of the installed DRAM chips. When Disabled, you can select the DRAM timing type.

DRAM Data Integrity Mode

Select Parity or ECC (error-correcting code), according to the type of installed DRAM.

DRAM ECC/PARITY Select

Set this option according to the type of DRAM installed in your system: error-correcting code (ECC) or parity (default).

DRAM Enhanced Paging

When Enabled, the chipset keeps the page open until a page/row miss. When Disabled, the chipset uses additional information to keep the DRAM page open when the host may be "right back."

DRAM Fast Leadoff

Select Enabled to shorten the leadoff cycles and optimize performance.

DRAM Last Write to CAS#

Select the number of cycles elapse between the last data signal and CAS# asserted. This period is the setup time for the CAS signal.

DRAM Leadoff Timing

Select the combination of CPU clocks the DRAM on your board requires before each read from or write to the memory. Changing the value from the setting determined by the board designer for the installed DRAM may cause memory errors.

DRAM Page Idle Timer

Select the amount of time in HCLKs that the DRAM controller waits to close a DRAM page after the CPU becomes idle.

DRAM Page Open Policy

When Disabled, the page open register is cleared and the corresponding memory page is closed. When Enabled, the page remains open, even when there are no requests to service.

DRAM Posted Write

See DRAM Posted Write Buffer, next.

DRAM Posted Write Buffer

The chipset maintains its own internal buffer for DRAM writes. When this buffer is Enabled, CPU write cycles to DRAM are posted to the buffer, so the CPU can start another write cycle before the DRAM finishes its cycle.

DRAM R/W Leadoff Timing

Select the combination of CPU clocks the DRAM on your board requires before each read from or write to the memory. Changing the value from the setting determined by the board designer for the installed DRAM may cause memory errors.

DRAM RAS Only Refresh

An alternate to CAS-before-RAS refresh. Leave Disabled unless your DRAM requires this older method of refresh generation.

DRAM RAS# Precharge Time

Select the number of CPU clocks allocated for the Row Address Strobe (RAS#) signal to accumulate its charge before the DRAM is refreshed. If insufficient time is allowed, refresh may be incomplete and data lost.

DRAM RAS# Pulse Width

The system designer must select the number of CPU clock cycles allotted for the RAS pulse refresh, according to DRAM specifications.

DRAM Read Burst (B/E/F)

Set the timing for burst-mode reads from DRAM. The lower the timing numbers, the faster the system addresses memory.

DRAM Read Burst (EDO/FPM)

Sets the timing for reads from EDO (Extended Data Output) or FPM (Fast Page Mode) memory. The lower the timing numbers, the faster the system addresses memory. Selecting timing numbers lower than the installed DRAM is able to support can result in memory errors.

DRAM Read Prefetch Buffer

Each time there is a memory access request, a preprogrammed number of local bus clock signals is counted down. When the count reaches zero, if the number of filled posted write buffer slots is at or above a predetermined threshold value, the memory request priority is raised. This mechanism is used to control memory access latency.

DRAM Read Wait State

These DRAM timing numbers are the pattern of cycles the CPU uses to read data from the main memory. The system board designer must select the proper combination, depending on the memory size and access speed of the DRAMs. Do not reset this option from its default.

DRAM Read/Write Timing

Your system designer should select the timing that the system uses when reading from and writing to DRAM. Do not reset from the factory default value.

DRAM Read-Around-Write

DRAM optimization feature: If a memory read is addressed to a location whose latest write is being held in a buffer before being written to memory, the read is satisfied through the buffer contents, and the read is not sent to the DRAM.

DRAM Refresh Period

Select the period required to refresh the DRAMs, according to DRAM specifications.

DRAM Refresh Queue

Enabled permits queuing up to four DRAM refresh requests, so DRAM can refresh at optimal times. Disabled makes all refreshes priority requests. Installed DRAM must support this feature; most do.

DRAM Refresh Rate

Select the period required to refresh the DRAMs, according to DRAM specifications.

DRAM Refresh Stagger By

Select the number of clock ticks (0-7) between refreshing rows in the memory array. Selecting 0 refreshes all rows at once.

DRAM R/W Leadoff Timing

Select the combination of CPU clocks the DRAM on your board requires before each read from or write to the memory. Changing the value from the setting determined by the board designer for the installed DRAM may cause memory errors.

DRAM Slow Refresh

The default DRAM refresh request signal occurs every 15 µs. A 16-bit ISA bus master may activate a refresh request when it has bus ownership. Selecting a slow refresh period here specifies the timing of the refresh request signal from an ISA master.

DRAM Speculative Leadoff

A read request from the CPU to the DRAM controller includes the memory address of the desired data. When Enabled, Speculative Leadoff lets the DRAM controller pass the read command to memory slightly before it has fully decoded the address, thus speeding up the read process.

DRAM Speed Selection

The value in this field must correspond to the speed of the DRAM installed in your system. DO NOT change the default setting of this field, as determined by the system board manufacturer for the installed DRAM. This value is access speed, so a lower value means a faster system.

DRAM Timing

The value in this field depends on performance parameters of the installed memory chips (DRAM). Do not change the value from the factory setting unless you install new memory that has a different performance rating than the original DRAMs.

DRAM Timing Control

This allows you to determine the type of timing the system uses when reading or writing to DRAM. Selections are Fast, Fastest, Normal (default) and Slow.

This field provides an alternative method of selecting DRAM timing. Again, the selected value must be set by the board designer, according to specifications of the installed DRAM and other board components. Turbo mode reduces CAS access time by 1 clock tick. VP2

DRAM to PCI RSLP

When Enabled, the chipset permits prefetching of two lines of data from system memory to the PCI bus.

DRAM Write Burst (B/E/F)
DRAM Write Burst Timing

Sets the timing for burst-mode writes from DRAM. The lower the timing numbers, the faster the system addresses memory. Selecting timing numbers lower than the installed DRAM is able to support can result in memory errors.

DRAM Write Wait State

The system board designer may elect to insert a wait state into the DRAM write cycle, if necessary.

DREQ6 PIN as

This field lets the board designer invoke a software suspend routine by toggling the DREQ6 signal. Select Suspend SW only if your board has such a feature.

Drive A
Drive B

Select the correct specifications for the diskette drive(s) installed in the computer.

None

No diskette drive installed

360K, 5.25 in

5-1/4 inch PC-type standard drive; 360 kilobyte capacity

1.2M, 5.25 in

5-1/4 inch AT-type high-density drive; 1.2 megabyte capacity

720K, 3.5 in

3-1/2 inch double-sided drive; 720 kilobyte capacity

1.44M, 3.5 in

3-1/2 inch double-sided drive; 1.44 megabyte capacity

2.88M, 3.5 in

3-1/2 inch double-sided drive; 2.88 megabyte capacity

Drive NA before BRDY

When Enabled, the NA signal is driven for one clock before the last BRDY# of every cycle for read/write hit cycles, thus generating ADS# in the next cycle after BRDY#, eliminating one dead cycle.

DRQ Detection

When Enabled, any activity on a DRQ signal line wakes up the system or resets the inactivity timer.

Duplex Select

In an infrared port mode, this field appears. Full-duplex mode permits simultaneous two-direction transmission. Half-duplex mode permits transmission in one direction only at a time. Select the value required by the IR device connected to the IR port.

E

ECP Mode Use DMA

Select a DMA channel for the port.

EDO CASx# MA Wait State

The board designer may elect to insert one additional wait state before the assertion of the first CASx# for page hit cycles, thus allowing one additional clock of MA setup time to the CASx# for the leadoff page hit cycle. Do not change from the manufacturer's default unless you are getting memory addressing errors. This field applies only if EDO DRAM is installed in the system.

EDO Back-to-Back Timing

Select the number of timer ticks required for back-to-back accesses, according to the specifications of installed EDO DRAM. SIS5571

EDO DRAM Read Burst

Set the timing for burst-mode reads from DRAM. The lower the timing numbers, the faster the system addresses memory. This field applies only if EDO DRAM is installed in the system.

EDO DRAM Speed Selection

The value in this field must correspond to the speed of the DRAM installed in your system. DO NOT change the default setting of this field, as determined by the system board manufacturer for the installed DRAM. This value is access speed, so a lower value means a faster system. This field applies only if EDO DRAM is installed in the system.

EDO DRAM Write Burst

Set the timing for burst-mode writes from DRAM. The lower the timing numbers, the faster the system addresses memory. This field applies only if EDO DRAM is installed in the system.

EDO RASx# Wait State

The board designer may elect to insert one additional wait state before RAS# is asserted for row misses, thus allowing one additional MAX[13:0] setup time to RASx# assertion. This field applies only if EDO DRAM is installed in the system.

EDO RAS# Precharge Time

The precharge time is the number of cycles it takes for the RAS to accumulate its charge before DRAM refresh. If insufficient time is allowed, refresh may be incomplete and the DRAM may fail to retain data. This field applies only if EDO DRAM is installed in the system.

EDO RAS# to CAS# Delay

This field applies only if EDO DRAM is installed in the system. It lets you insert a timing delay between the CAS and RAS strobe signals, used when DRAM is written to, read from, or refreshed. Disabled gives faster performance; and Enabled gives more stable performance.

EDO is short for Extended Data Output. EDO DRAM is faster than conventional DRAM if the cache controller in the system supports pipeline burst transfer mode. Unlike conventional DRAM, which only allows one byte to be read at a time, EDO DRAM can copy an entire block of memory to its internal cache. While the processor is accessing this cache, the memory can collect a new block to send.

EDO Read WS

Select the correct cycle timing combination for the system board design and EDO DRAM specifications.

Enhanced Memory Write

Select Enabled or Disabled for the Memory Write and Invalidate command on the PCI bus. This field must be Disabled if cache size is 512 KB and the tag address is 8 bits.

Enhanced Page Mode

Select Enabled or Disabled, according to DRAM specifications.

EPP Version

Select EPP port type 1.7 or 1.9.

Extended CPU-PIIX4 PHLDA#

When Enabled, the system controller adds one clock signal to the length of time the PHLDA# signal is active under two conditions:

During the address phase at the beginning of a PCI read/write transaction

Following the address phase of a CPU LOCK cycle

When this field is Enabled, the Passive Release and Delayed Transaction fields should be Enabled.

Extended Read-Around-Write

When Enabled, reads can bypass writes within the 82450GX memory interface component(s), provided their addresses do not match.

External Cache

Cache memory is additional memory that is much faster than conventional DRAM (system memory). Most, but not all, modern PCs have additional (external) cache memory. When the CPU requests data, the system transfers the requested data from the main DRAM into cache memory, for even faster access by the CPU.

Extra AT Cycle WS

Select Enabled to insert one wait state in the standard AT bus cycle. Normally used when Legacy peripherals require additional response time.

F

Fast AT Cycle

Select Enabled to shorten AT bus cycles by one ATCLK signal.

Fast Back-to-Back

When Enabled, consecutive write cycles targeted to the same slave become fast back-to-back on the PCI bus.

Fast DRAM Refresh

The cache DRAM controller offers two refresh modes, Normal and Hidden. In both modes, CAS takes place before RAS but the Normal mode requires a CPU cycle for each. On the other hand, a cycle is eliminated by "hiding" the CAS refresh in Hidden mode. Not only is the Hidden mode faster and more efficient, but it also allows the CPU to maintain the status of the cache even if the system goes into Suspend power-management mode.

Fast EDO Leadoff

Select Enabled only for EDO DRAMs in either a synchronous cache or a cacheless system. It causes a 1-HCLK pull-in for all read leadoff latencies for EDO DRAMs (i.e., page hits, page misses, and row misses). Select Disabled if any of the DRAM rows are populated with FPM DRAMs.

Fast EDO Path Select

When Enabled, a fast path is selected for CPU-to-DRAM read cycles for the leadoff, providing the system contains EDO DRAMs. It causes a 1-HCLK pull-in for all read leadoff latencies (i.e., page hits, page misses, and row misses).

Fast MA to RAS# Delay [CLK]

The values in this field are set by the system board designer, depending on the DRAM installed. Do not change the values in this field unless you change specifications of the installed DRAM or the installed CPU.

Fast RAS to CAS Delay

When DRAM is refreshed, both rows and columns are addressed separately. This setup item allows you to determine the timing of the transition from RAS to Column Address Strobe (CAS).

FDD Detection

When Enabled, any floppy drive activity wakes up the system or resets the inactivity timer.

Floppy 3 Mode Support

When Enabled, the BIOS supports a type of 3.5-in diskette drive that can read 720-KB, 1.2-MB, and 1.44-MB diskettes.

G

Gate A20 Option

Gate A20 refers to the way the system addresses memory above 1 MB (extended memory). When set to Fast, the system chipset controls Gate A20. When set to Normal, a pin in the keyboard controller controls Gate A20. Setting Gate A20 to Fast improves system speed, particularly with OS/2 and Windows.

Global Standby Timer

After the selected period of inactivity for the entire system, the system enters Standby mode.

Global Suspend Timer

After the selected period of global Standby mode, the system enters Suspend mode.

GPI05 Power Up Control

When you select Enabled, a signal from General Purpose Input 05 returns the system to Full On state. SIS5597

Graphic Posted Write Buff

The chipset maintains its own internal buffer for graphics memory writes. When this buffer is Enabled, CPU write cycles to graphics memory are posted to the buffer, so the CPU can start another write cycle before the graphics memory finishes its cycle.

Guaranteed Access Time

When Enabled, Guaranteed Access Time mode is enabled, so a CHRDY time-out of 2.5 (s is guaranteed for the ISA bus. When Disabled, an ISA bus master is granted the ISA bus and then the SIO chip arbitrates for the PCI bus.

H

Halt On

During the power-on self-test (POST), the computer stops if the BIOS detects a hardware error. You can tell the BIOS to ignore certain errors during POST and continue the boot-up process. These are the selections:

No errors

POST does not stop for any errors.

All errors

If the BIOS detects any non-fatal error, POST stops and prompts you to take corrective action.

All, But Keyboard

POST does not stop for a keyboard error, but stops for all other errors.

All, But Diskette

POST does not stop for diskette drive errors, but stops for all other errors.

All, But Disk/Key

POST does not stop for a keyboard or disk error, but stops for all other errors.

Hard Disks

The BIOS supports up to four IDE drives. This section does not show information about other IDE devices, such as a CD-ROM drive, or about other hard drive types, such as SCSI drives.

NOTE: We recommend that you select type AUTO for all drives.

The BIOS can automatically detect the specifications and optimal operating mode of almost all IDE hard drives. When you select type AUTO for a hard drive, the BIOS detects its specifications during POST, every time the system boots.

If you do not want to select drive type AUTO, other methods of selecting the drive type are available:

7. Match the specifications of your installed IDE hard drive(s) with the preprogrammed values for drive types 1 through 45.

8. Select USER and enter values into each drive parameter field.

9. Use the IDE HDD AUTO DECTECTION function in Setup.

Here is a brief explanation of drive specifications:

§ Type: The BIOS contains a table of pre-defined drive types. Each defined drive type has a specified number of cylinders, number of heads, write precompensation factor, landing zone, and number of sectors. Drives whose specifications do not accommodate any pre-defined type are classified as type USER.

§ Size: Disk drive capacity (approximate). Note that this size is usually slightly greater than the size of a formatted disk given by a disk-checking program.

§ Cyls: Number of cylinders

§ Head: Number of heads

§ Precomp: Write precompensation cylinder

§ Landz: Landing zone

§ Sector: Number of sectors

§ Mode: Auto, Normal, large, or LBA

§ Auto: The BIOS automatically determines the optimal mode.

§ Normal: Maximum number of cylinders, heads, and sectors supported are 1024, 16, and 63.

§ Large: For drives that do not support LBA and have more than 1024 cylinders. Applicable to only a few drives.

§ LBA (Logical Block Addressing): During drive accesses, the IDE controller transforms the data address described by sector, head, and cylinder number into a physical block address, significantly improving data transfer rates. For drives with greater than 1024 cylinders.

HDD Detection

When Enabled, any hard drive activity wakes up the system or resets the inactivity timer.

HDD Off After

After the selected period of drive inactivity, the hard disk drive powers down while all other devices remain active. Selecting Suspend tells the drive to power down immediately.

HDD Power Down

After the selected period of drive inactivity, the hard disk drive powers down while all other devices remain active.

HDD Standby Timer

After the selected period of drive inactivity, the hard disk drive powers down. Its timing is separate from other PM modes listed above.

Hidden Refresh

When Disabled, DRAM is refreshed by IBM AT methodology, using a CPU cycles for each refresh. When hidden refresh is Enabled, the DRAM controller seeks the most opportune moment for a refresh, regardless of CPU cycles, with least disruption of system activity and least performance penalty. Hidden refresh is faster and more efficient, and it also allows the CPU to maintain the status of the DRAM even if the system goes into a power management "suspend" mode.

Host-to-PCI Bridge Retry

When Enabled, the peripherals controller (PIIX4) retries, without initiating a delayed transaction, CPU-initiated nonLOCK# PCI cycles. No delayed transactions to the controller may be currently pending and passive release must be active. When this field is Enabled, the Passive Release and Delayed Transaction fields should be Enabled.

Hot Key Power Off

Select Enabled if your system has a hot key for soft power off. SIS5597

I

I/O Recovery Time

The peripheral controller insert a minimum of 2 bus clock (BCLK) delays between back-to-back 8- or 16-bit ISA I/O cycles issued from the PCI master. If a greater delay is desired, select 4, 8, 12 clocks.

IDE 32-bit Transfer Mode

The IDE interface in the integrated peripherals controller supports 32-bit data transfers. Select enabled only if your IDE hard drives can also support 32-bit transfer mode.

IDE Buffer for DOS & Win

Select Enabled to increase throughput to and from IDE devices by using the on-chip read-ahead and posted-write IDE buffers. Note that use of the buffers may cause some slow IDE devices to be even slower. When in doubt, experiment with this setting for optimal performance and data integrity.

IDE Burst Mode

Selecting Enabled reduces latency between each drive read/write cycle, but may cause instability in IDE subsystems that cannot support such fast performance. If you are getting disk drive errors, try setting this value to Disabled. This field does not appear when the Internal PCI/IDE field is Disabled.

IDE Data Port Post Write

Selecting Enabled speeds up processing of drive reads and writes, but may cause instability in IDE subsystems that cannot support such fast performance. If you are getting disk drive errors, try setting this value to Disabled.

IDE HDD Block Mode

Block mode is also called block transfer, multiple commands, or multiple sector read/write. If your IDE hard drive supports block mode (most new drives do), select Enabled for automatic detection of the optimal number of block read/writes per sector the drive can support.

IDE Prefetch Mode

The onboard IDE drive interfaces supports IDE prefetching, for faster drive accesses. If you install a primary and/or secondary add-in IDE interface, set this field to Disabled if the interface does not support prefetching.

IDE Primary/ Secondary Master/Slave PIO

The four IDE PIO (Programmed Input/Output) fields let you set a PIO mode (0-4) for each of the four IDE devices that the onboard IDE interface supports. Modes 0 through 4 provide successively increased performance. In Auto mode, the system automatically determines the best mode for each device.

IDE Primary/ Secondary Master/Slave UDMA

UDMA (Ultra DMA) is a DMA data transfer protocol that utilizes ATA commands and the ATA bus to allow DMA commands to transfer data at a maximum burst rate of 33 MB/s. When you select Auto in the four IDE UDMA fields (for each of up to four IDE devices that the internal PCI IDE interface supports), the system automatically determines the optimal data transfer rate for each IDE device.

IDE Second Channel Control

The chipset contains a PCI IDE interface with support for two IDE channels. Select Enabled to activate the secondary on-chip IDE interface. Select Disabled to deactivate this interface, if you install a secondary add-in IDE interface.

In Order Queue Depth

Select 8 to track up to eight pipelined bus transactions.

IN0-IN6 (V)

These fields display the current voltage of up to seven voltage input lines, if your computer contains a monitoring system.

Inactive Timer Select

Select the timeout period (period of system inactivity) after which the system enters Inactive mode. This period should be longer than the period selected for Standby mode.

Init AGP Display First
Init Display First

Initialize the AGP video display before initializing any other display device on the system. Thus the AGP display becomes the primary display.

Internal PCI/IDE

The chipset contains a PCI IDE interface that supports two IDE channels: Primary (IRQ 14) and Secondary (IRQ 15). Each channel supports two IDE devices, so the system is capable of supporting a total of four IDE devices. Select Primary, Secondary, or Both to activate chipset IDE interface(s) installed on your system board.

InfraRed Duplex Type
IR Function Duplex

Select the value required by the IR device connected to the IR port. Full-duplex mode permits simultaneous two-direction transmission. Half-duplex mode permits transmission in one direction only at a time. If no infrared port is present in the system, select Disabled.

IR Duplex Mode

Select the value required by the IR device connected to the IR port. Full-duplex mode permits simultaneous two-direction transmission. Half-duplex mode permits transmission in one direction only at a time. If no infrared port is present in the system, select Disabled.

IRQ n Assigned to

When resources are controlled manually, assign each system interrupt as one of the following types, depending on the type of device using the interrupt:

Legacy ISA:

Devices compliant with the original PC AT bus specification, requiring a specific interrupt (such as IRQ4 for serial port 1)

PCI/ISA PnP:

Devices compliant with the Plug and Play standard, whether designed for PCI or ISA bus architecture.

IRQ8 Break Suspend
IRQ8 Break [Event From] Suspend

You can Enable or Disable monitoring of IRQ8 (the Real Time Clock) so it does not awaken the system from Suspend mode.

IRQ8 Clock Event..

You can turn On or Off monitoring of IRQ8 (the Real Time Clock) so it does not awaken the system from Suspend mode.

IRQn Detection

When Enabled, any activity from the selected IRQ (IRQ3-IRQ12; IRQ14-IRQ15) wakes up the system or resets the inactivity timer.

IRRX Mode Select

This field appears only when IrDA mode 1.1 is selected for UART2 Mode. The value in this field depends on the type of transceiver module used for IrDA mode 1.1 (called fast IR). One type has a mode pin (IRMODE) and the other type has a second receive data channel (IRRX3). Do not change the factory default value of this field unless your IR peripheral documentation explicitly states a mode requirement for fast IR, or if you are having a problem configuring your IR peripheral in fast IR mode.

ISA Bus Clock

You can set the speed of the AT bus at one-third or one-fourth of the CPU clock speed.

ISA Bus Clock Option
ISA Bus Clock Frequency

The ISA bus clock speed is the speed at which the CPU communicates with the AT bus (expansion bus). The speed is measured as a fraction of PCICLKI, the timing signal of the PCI bus. Experiment with setting the bus timing to a lower speed (for example, from PCICLKI/3 to PCICLKI/4) if an installed expansion peripheral has performance problems.

ISA Clock

You can set the speed of the AT bus at one-third or one-fourth of the CPU clock speed.

ISA I/O Recovery

The CPU and local bus are much faster than industry standard architecture (ISA) input/output (I/O) bus. Select Enabled to allow additional time for I/O devices to respond to the system. Otherwise, data could be lost. If all your I/O devices are capable of fast I/O, selecting Disabled can speed up processing.

ISA Line Buffer

The PCI to ISA Bridge has an 8-byte bidirectional line buffer for ISA or DMA bus master memory reads from or writes to the PCI bus. When Enabled, an ISA or DMA bus master can prefetch two doublewords to the line buffer for a read cycle.

J

Joystick Function

If your system has a joystick peripheral, select Enable.

K

KBC input clock

The system designer must select the correct frequency for the keyboard controller input clock. Do not change this value from the default value.

Keyboard Controller Clock

The keyboard controller clock speed is the speed at which the CPU communicates with the keyboard controller. Depending on the specifications of the installed keyboard controller, the speed may be fixed at 7.16 MHz or may be a fraction of PCICLKI, the timing signal of the PCI bus.

Keyboard Emulation

When Enabled, Gate A20 and software reset emulation for an external keyboard controller are enabled. Be sure to make the setting of this field agree with the setting of the Gate A20 Option field in the BIOS Features Setup screen (Fast = Enabled; Normal = Disabled).

Keyboard Resume

When Disabled, keyboard activity does NOT awaken the system from Suspend mode. VP2

L

L1 Cache Policy

Write-Through means that memory is updated with data held in the cache whenever the CPU issues a write cycle. On the other hand, Write-Back causes memory to be updated only under certain conditions, such as read requests to the memory whose contents are currently in the cache. Write-Back allows the CPU to operate with fewer interruptions, increasing its efficiency.

L2 Cache Cacheable Size

Select 512 MB only if your system RAM is greater than 64 MB.

L2 Cache Write Policy

In addition to the Write-Back and Write-Through options, the L2 cache also offers Adaptive WB1 and Adaptive WB2. Both adaptive write-back modes try to reduce the disadvantages of both the write-through and write-back policies. The system designer must select the optimal cache write policy, according to the SRAM specifications.

L2 to PCI Read Buffer

The chipset maintains its own internal buffer for external-cache-to-PCI writes. When this buffer is Enabled, external cache write cycles to the PCI bus are posted to the buffer, so the each device can complete its cycles without waiting for the other.

L2 (WB) Tag Bit Length

The system uses tag bits to determine the status of data in the cache. Set this field to match the specifications (7 or 8 bits) of the system external cache.

LCD&CRT

Select your video display device:

LCD

Notebook liquid crystal display

CRT

Auxiliary monitor

AUTO

The BIOS autosenses the device in use (this value lets you switch between devices without being left "in the dark").

LCD&CRT

Display on both devices

LDEV Detection

When Enabled, any activity on the LDEV signal line wakes up the system or resets the inactivity timer.

Linear Merge

When Enabled, only consecutive linear addresses can be merged.

Linear Mode SRAM Support

Select Enabled if your system contains a CPU that requires linear mode (e.g., Cyrix M1/M2 CPU).

Local Memory 15-16M

To increase performance, your system can map slower device memory (usually a device is connected to the slower ISA bus) into much faster local bus memory. It does this by setting aside local memory and transferring the start point from the device memory to the local memory. Use this setting to enable/disable this capability. It is Enabled by default.

LREQ Detection

When Enabled, any activity on the LREQ signal line wakes up the system or resets the inactivity timer.

M

M1 Linear Burst Mode

Select Enabled if your system contains a Cyrix M1 CPU.

MA Additional Wait State

Selecting Enabled inserts an additional wait state before the beginning of a memory read. The setting of this parameter depends on the board design. Do not change from the manufacturer's default unless you are getting memory addressing errors.

Master Mode Byte Swap
Master Byte Swap Control

Select Enabled or Disabled.

Master Retry Timer

This sets how many PCI clock signals the CPU master attempts a PCI cycle before the cycle is unmasked (terminated).

Mem. Drive Str. (MA/RAS)

(Memory Address Drive Strength) This field controls the strength of the output buffers driving the MA and BA1 pins (first value) and SRASx#, SCASx#, MWEx#, and CKEx pins (second value).

Memory

You cannot change any values in the Memory fields; they are only for your information. The fields show the total installed random access memory (RAM) and amounts allocated to base memory, extended memory, and other (high) memory. RAM is counted in kilobytes (KB: approximately one thousand bytes) and megabytes (MB: approximately one million bytes).

RAM is the computer's working memory, where the computer stores programs and data currently being used, so they are accessible to the CPU. Modern personal computers may contain up to 64 MB, 128 MB, or more.

Base Memory

Typically 640 KB. Also called conventional memory. The DOS operating system and conventional applications use this area.

Extended Memory

Above the 1-MB boundary. Early IBM personal computers could not use memory above 1 MB, but current PCs and their software can use extended memory.

Other Memory

Between 640 KB and 1 MB; often called High memory. DOS may load terminate-and-stay-resident (TSR) programs, such as device drivers, in this area, to free as much conventional memory as possible for applications. Lines in your CONFIG.SYS file that start with LOADHIGH load programs into high memory.

Memory Hole at 15M Addr.

You can reserve this area of system memory for ISA adapter ROM. When this area is reserved, it cannot be cached. The user information of peripherals that need to use this area of system memory usually discusses their memory requirements.

Memory Hole at 15M-16M

You can reserve this area of system memory for ISA adapter ROM. When this area is reserved, it cannot be cached. The user information of peripherals that need to use this area of system memory usually discusses their memory requirements.

Memory Parity Check

Select Enabled if the DRAM chips in your system support parity.

Memory Parity/ECC Check

Select Enabled, Disabled, or Auto. In Auto mode, the BIOS enables memory checking automatically when it detects the presence of ECC or parity DRAM.

MODEM Use IRQ

Name the interrupt request (IRQ) line assigned to the modem (if any) on your system. Activity of the selected IRQ always awakens the system.

Monitor Event in Full On Mode

In On mode, the Standby timer (Standby Timer Select, 2-256 min) starts counting if no activity is taking place and the programmable time-out period has expired.

When you Enabled monitoring (checking) of a device listed under this category, it is included in the list of devices that the system monitors during the PM timers count-down.

When you Disable monitoring (checking) of a device listed under this category, activity does not interrupt the PM timers count-down.

Month Alarm

Select a month (1-12) or NA if you want the alarm active during all months. SIS5597

MPS Version Control for OS

The BIOS supports versions 1.1 and 1.4 of the Intel multiprocessor specification. Select the version supported by the operating system running on this computer.

MPU-401 Configuration

Select Enabled to configure the MPU-401 interface.

MPU-401 I/O Base Address

Select a base I/O address for the MPU-401 interface

N

NA# Enable

Selecting Enabled permits pipelining, in which the chipset signals the CPU for a new memory address before all data transfers for the current cycle are complete, resulting in faster performance.

O

Onboard Audio Chip

Select Enabled to use the audio capabilities of your system. Most of the following fields do not appear when this field is Disabled.

Onboard FDC/FDD Controller

Select Enabled if your system has a floppy disk controller (FDC) installed on the system board and you wish to use it. If you install an add-in FDC or the system has no floppy drive, select Disabled in this field.

Onboard IDE Controller

The chipset contains a PCI IDE interface with support for two IDE channels. Select Primary to activate the only primary IDE interface, if you install an add-in secondary interface. Select Both to activate both interfaces, or Disabled to deactivate both interfaces, if you install both a primary and a secondary add-in IDE interface.

Onboard Parallel Port

Select a logical LPT port address and corresponding interrupt for the physical parallel port.

Onboard PCI SCSI Chip

Select Enabled if your system contains a built-in PCI SCSI controller.

Onboard Serial Ports (1/2, A/B)

Select a logical COM port name and matching address for the first and second serial ports. Select an address and corresponding interrupt for the first and second serial ports.

Onboard UART 1/2

See Onboard Serial Ports, above.

Onboard UART 1/2 Mode

See UART 2 Mode. Available modes apply to selected serial port.

On-Chip IDE Controller

The integrated peripheral controller contains a IDE interface with support for two IDE channels. Select Enabled to activate the IDE interface.

On-Chip IDE First/Second Channel

The chipset contains a PCI IDE interface with support for two IDE channels. Select Enabled to activate the first and/or second IDE interface. Select Disabled to deactivate an interface, if you install a primary and/or secondary add-in IDE interface.

On-Chip Local Bus IDE

The chipset contains an enhanced IDE interface with two IDE channels. Because each channel supports two IDE devices, the system supports a total of four IDE devices. If your system board has one or two IDE connectors, this option should be Enabled. If you install an add-in IDE interface, disable one or both on-chip IDE channels.

On-Chip PCI IDE

The chipset contains a PCI IDE interface with support for two IDE channels. Select Enabled to activate the IDE interface. Select Disabled to deactivate this interface, if you install a primary and/or secondary add-in IDE interface. You can disable the second IDE interface separately in the IDE Second Channel Control field in the BIOS Features Setup screen.

On-Chip Primary/ Secondary PCI IDE

The integrated peripheral controller contains an IDE interface with support for two IDE channels. Select Enabled to activate each channel separately.

OS Select for DRAM > 64MB

Select OS2 only if you are running OS/2 operating system with greater than 64 MB of RAM on your system.

P

Page Hit Control

This function is used for testing the controller.

Page Mode Read WS

Select the correct cycle timing combination for the system board design and Page Mode DRAM specifications.

Parallel Port EPP Type

Select EPP port type 1.7 or 1.9, as required by your parallel peripheral.

Parallel Port Mode

Select an operating mode for the onboard parallel (printer) port. Select Normal, Compatible, or SPP unless you are certain your hardware and software both support one of the other available modes.

For information about parallel port modes, see http://www.fapo.com/1284int.htm

Passive Release

When Enabled, CPU to PCI bus accesses are allowed during passive release. Otherwise, the arbiter only accepts another PCI master access to local DRAM.

PCI 2.1 Compliance

Select Enabled to support compliance with PCI specification version 2.1.

PCI Arbitration Mode

The method by which the PCI bus determines which bus master device gains access to the bus. Typically, the system manages or arbitrates access to the PCI bus on a first-come-first-served basis. When priority is rotated, once a device gains control of the bus it is assigned the lowest priority and every other device is moved up one in the priority queue.

PCI Burst

When Enabled, data transfers on the PCI bus, where possible, make use of the high-performance PCI burst protocol, in which greater amounts of data are transferred at a single command.

If the write transaction is a burst transaction, the information goes into the write buffer and burst transfers are later performed on the PCI bus. If the transaction is not a burst, PCI write occurs immediately (after a write buffer flush). VP2

PCI Burst Write Combine

When this option is Enabled, the chipset assembles long PCI bursts from the data held in these buffers.

PCI CLK

The system board designer selects whether the PCI clock is tightly synchronized with the CPU clock or is asynchronous.

PCI Delayed Transaction

The chipset has an embedded 32-bit posted write buffer to support delay transactions cycles. Select Enabled to support compliance with PCI specification version 2.1.

PCI Dynamic Bursting

When Enabled, every write transaction goes to the write buffer. Burstable transactions then burst on the PCI bus and nonburstable transactions do not. VP2

PCI Fast Back to Back Wr

When Enabled, the PCI bus interprets CPU read cycles as the PCI burst protocol, so back-to-back sequential CPU memory read cycles addressed to the PCI bus will be translated into fast PCI burst memory cycles.

PCI IDE 2nd Channel

Since your chipset supports a second IDE channel, you can use this selection to enable or disable the second channel. The second channel may connect to a CD-ROM.

PCI IDE Controller

The chipset contains a PCI IDE interface that is permanently configured as the secondary IDE channel. Select Secondary to activate this IDE interface. Select Disabled to deactivate this interface, if you install an add-in secondary IDE interface.

PCI IDE IRQ Map to

This field lets you select PCI IDE IRQ mapping or PC AT (ISA) interrupts. If your system does not have one or two PCI IDE connectors on the system board, select values according to the type of IDE interface(s) installed in your system (PCI or ISA). Standard ISA interrupts for IDE channels are IRQ14 for primary and IRQ15 for secondary.

PCI IRQ Activated by

Leave the IRQ trigger set at Level unless the PCI device assigned to the interrupt specifies Edge-triggered interrupts.

PCI Master 0 WS Write

When Enabled, writes to the PCI bus are executed with zero wait states.

PCI Mem Line Read

When Enabled, PCI Memory Read Line commands fetch full cache lines. When Disabled, a PCI Memory Read Line command results in read partials on the CPU bus.

PCI Mem Line Read Prefetch

When Enabled, PCI Memory Commands fetch a full cache line plus a prefetch of up to three additional full cache lines. Prefetching does not cross 4-KB address boundaries. When Disabled, no line prefetching is performed for PCI Memory Read Line commands. This field is irrelevant if PCI Mem Line Read, above, is Disabled.

PCI Passive Release

When Enabled, CPU to PCI bus accesses are allowed during passive release. Otherwise, the arbiter only accepts another PCI master access to local DRAM.

PCI Posted Write Buffer

You can Enable or Disable the chipset's ability to use a buffer for posted writes initiated on the PCI bus.

PCI Preempt Timer

Set the length of time (in LCLK ticks) before one PCI master preempts another when a service request is pending.

PCI Pre-Snoop

Pre-snooping is a technique by which a PCI master can continue to burst to local memory until a 4K page boundary is reached rather than just a line boundary.

PCI Read burst WS

Select the number of cycles allotted for a PCI master burst read.

PCI Slot IDE 2nd Channel

You may separately disable the second channel on an IDE interface installed in a PCI expansion slot.

PCI Timeout

When Disabled, the PCI cycles is disconnected if the first data access is not completed with 16 PCI clocks. When Enabled, the PCI cycles remains connected, even if the first data access is not completed with 16 PCI clocks.

PCI to DRAM Buffer

Your system supports buffered writes from the PCI bus to DRAM for greater efficiency.

PCI to L2 Write Buffer

The chipset maintains its own internal buffer for PCI-to-external-cache writes. When this buffer is Enabled, PCI write cycles to the external cache are posted to the buffer, so the each device can complete its cycles without waiting for the other.

PCI Write Burst

When Enabled, consecutive PCI write cycles become burst cycles on the PCI bus.

PCI Write burst WS

Select the number of cycles allotted for a PCI master burst write.

PCI/VGA Palette Snoop

Leave this field at Disabled.

PCI-To-CPU Write Posting

When this field is Enabled, writes from the PCI bus to the CPU are buffered, so the PCI bus can continue writing while the CPU is occupied with other processing. When Disabled, the writes are not buffered and the PCI bus must wait until the CPU is free before starting another write cycle.

PCI-To-DRAM Pipeline

DRAM optimization feature: If Enabled, full PCI-to-DRAM write pipelining is enabled. Buffers in the chipset store data written from the PCI bus to memory. When Disabled, PCI writes to DRAM are limited to a single transfer per write cycle.

Peer Concurrency

Peer concurrency means that more than one PCI device can be active at a time.

Pipeline

Select Enabled to enable the cache pipeline function when pipelined synchronous cache SRAM is installed in the system.

Pipeline Cache Timing

For a secondary cache of one bank, select Faster. For a secondary cache of two banks, select Fastest.

Pipelined Function

When Enabled, the controller signals the CPU for a new memory address before all data transfers for the current cycles are complete, resulting in faster performance.

PM Control by APM

If Advanced Power Management (APM) is installed on your system, selecting Yes gives better power savings.

PM Events

You may disable activity monitoring of some common I/O events and interrupt requests so they do not wake up the system. The default wake-up event is keyboard activity. When On (or named, in the case of LPT & COM), any activity from one of the listed system peripheral devices or IRQs wakes up the system.

A power-management (PM) event awakens the system from, or resets activity timers for, Suspend mode. You can disable monitoring of common interrupt requests so they do not generate PM events. VP2

PM Mode

Power management is configured for SMI Green mode, which is the mode required by the system CPU.

PM wait for APM

If Advanced Power Management (APM) is installed on your system, selecting Yes gives better power savings.

PnP BIOS Auto-Config

The Award Plug and Play BIOS can automatically configure Plug and Play-compatible devices. If you select Enabled, the Available IRQ fields disappear, because the BIOS automatically handles their configuration.

PNP OS Installed

Select Yes if the system operating environment is Plug-and-Play aware (e.g., Windows 95).

Posted PCI Memory Writes

When this field is Enabled, writes from the PCI bus to memory are posted. This is an intermediate posting. If the CPU and PCI-to-DRAM posted write buffer in enabled, the data is interleaved with CPU write data and posted a second time before being written to DRAM.

Power Button Over Ride

When you select Enabled, pressing the power button for more than 4 seconds forces the system to enter the Soft-Off state when the system has "hung." <SIS5597

Power Down Activities

You may disable monitoring of common interrupt requests so they do not reset activity timers.

Power Down and Resume Events

1 You can disable monitoring of common interrupt requests so they do not awaken the system from, or reset activity timers for, Suspend mode.

2 Select ON if you want an IRQ, when accessed, to reload the original count of the global timer. Selected IRQs also cause the system to wake up from a global Doze, Standby, or Suspend mode when accessed.

The global timer is the hardware timer that counts down to Doze, Standby, and Suspend modes. If a doze timeout is set, the system enters Doze mode when the timeout expires. Then the timer reloads with the standby timeout, if one is set. If not, it reloads with the suspend timeout, if one is set. If not, the timer turns off. The timer works in a similar way for the standby and suspend timeouts. When more than one global timeout is set, the timeouts run one after the other.

Power Management

This option allows you to select the type (or degree) of power saving for Doze, Standby, and Suspend modes.
This table describes each power management mode:

Max Saving

Maximum power savings. Only Available for SL CPUs.

User Define

Set each mode individually.

Min Saving

Minimum power savings.

Power Up by Alarm

When you select Enabled, fields appear that let you set the alarm that returns the system to Full On state. SIS5597

Primary & Secondary IDE INT#

Each PCI peripheral connection is capable of activating up to four interrupts: INT# A, INT# B, INT# C and INT# D. By default, a PCI connection is assigned INT# A. Assigning INT# B has no meaning unless the peripheral device requires two interrupt services rather than just one. Because the PCI IDE interface in the chipset has two channels, it requires two interrupt services. The primary and secondary IDE INT# fields default to values appropriate for two PCI IDE channels, with the primary PCI IDE channel having a lower interrupt than the secondary.

Primary Frame Buffer

Select a size for the PCI frame buffer. The size of the buffer should not impinge on local memory.

PS/2 Mouse Function Control

If your system has a PS/2 mouse port and you install a serial pointing device, select Disabled.

Q

Quick Frame Generation

When the PCI-VL bus bridge is acting as a PCI Master and receiving data from the CPU, a fast CPU-to-PCI buffer is enabled if this selection is also enabled. Using the buffer allows the CPU to complete a write even though the data has not been delivered to the PCI bus. This reduces the number of CPU cycles involved and speeds overall processing.

Quick Power On Self Test

Select Enabled to reduce the amount of time required to run the power-on self-test (POST). A quick POST skips certain steps. We recommend that you normally disable quick POST. Better to find a problem during POST than lose data during your work.

R

RAMW# Assertion Timing

RAMW is an output signal to enable local memory writes. The system designer select Normal or Faster (by one timer tick) according to DRAM specifications.

RAS Precharge @Access End

When Enabled, RAS# remains asserted at the end of access ownership. When Disabled, RAS# is deasserted at the end of access ownership.

RAS Precharge Period
RAS Precharge Time

The precharge time is the number of cycles it takes for the RAS to accumulate its charge before DRAM refresh. If insufficient time is allowed, refresh may be incomplete and the DRAM may fail to retain data.

RAS Pulse Width
RAS Pulse Width Refresh

The system designer must select the number of CPU clock cycles allotted for the RAS pulse refresh, according to DRAM specifications.

RAS Timeout

When RAS timeout is Disabled, a memory refresh cycle is generated every 15 microseconds. Extra refresh cycles are generated when RAS timeout is Enabled.

RAS to CAS Delay Timing

When DRAM is refreshed, both rows and columns are addressed separately. This setup item allows you to determine the timing of the transition from RAS (row address strobe) to CAS (column address strobe).

RAS# to CAS# Address Delay

This field lets you insert a timing delay from the time RAS# is asserted to when Column Address is asserted.

RAS# to CAS# Delay

This field lets you insert a timing delay between the CAS and RAS strobe signals, used when DRAM is written to, read from, or refreshed. Disabled gives faster performance; and Enabled gives more stable performance.

Read-Around-Write

DRAM optimization feature: If a memory read is addressed to a location whose latest write is being held in a buffer before being written to memory, the read is satisfied through the buffer contents, and the read is not sent to the DRAM.

Read CAS# Pulse Width

The system designer must set the number of CPU cycles the CAS signal requires during a DRAM read operation.

Read Pipeline

You may select Enabled for this field when PBSRAMs are installed. Pipelining improves system performance. VP2

Read Prefetch Memory RD

When this item is Enabled, the system is allowed to prefetch the next read instruction and initiate the next process.

Reduce DRAM Leadoff Cycle

Selecting Enabled optimizes system DRAM performance by shortening the time required before memory read or write operations. The installed DRAM must support a reduced cycle.

Refresh Cycle Time (us)

Select the period required to refresh the DRAMs, according to DRAM specifications.

Refresh RAS# Assertion

Select the number of clock cycles in which RAS# is asserted for refresh cycles.

Reload Global Timer Events

When Enabled, an event occurring on each listed device restarts the global timer for Standby mode.

Report No FDD For WIN 95

Select Yes to release IRQ6 when the system contains no floppy drive, for compatibility with Windows 95 logo certification. In the Integrated Peripherals screen, select Disabled for the Onboard FDC Controller field.

Reset Configuration Data

Normally, you leave this field Disabled. Select Enabled to reset Extended System Configuration Data (ESCD) when you exit Setup if you have installed a new add-on and the system reconfiguration has caused such a serious conflict that the operating system cannot boot.

Resources Controlled By

The Plug and Play AwardBIOS can automatically configure all the boot and Plug and Play-compatible devices. If you select Auto, all the interrupt request (IRQ) and DMA assignment fields disappear, as the BIOS automatically assigns them.

Resume by Ring

An input signal on the serial Ring Indicator (RI) line (in other words, an incoming call on the modem) awakens the system from a soft off state.

RTC Alarm Resume

When Enabled, your can set the date and time at which the RTC (real-time clock) alarm awakens the system from Suspend mode. VP2

S

SDRAM Bank Interleave

Select 2 Bank or 4-Bank interleave for 64-Mb SDRAM. If 16-Mb SDRAM is installed, leave Disabled. VP2

SDRAM (CAS Lat/RAS-to-CAS)

You can select a combination of CAS latency and RAS-to-CAS delay in HCLKs of 2/2 or 3/3. The system board designer should set the values in this field, depending on the DRAM installed. Do not change the values in this field unless you change specifications of the installed DRAM or the installed CPU.

SDRAM CAS Latency
SDRAM CAS Latency Time

When synchronous DRAM is installed, the number of clock cycles of CAS latency depends on the DRAM timing. Do not reset this field from the default value specified by the system designer.

SDRAM Cycle Length

This field sets the CAS latency timing. VP2

SDRAM Precharge Control

When Enabled, all CPU cycles to SDRAM result in an All Banks Precharge Command on the SDRAM interface.

SDRAM RAS Precharge Time

If an insufficient number of cycles is allowed for the RAS to accumulate its charge before DRAM refresh, the refresh may be incomplete and the DRAM may fail to retain data. Fast gives faster performance; and Slow gives more stable performance. This field applies only when synchronous DRAM is installed in the system.

SDRAM RAS to CAS Delay

This field lets you insert a timing delay between the CAS and RAS strobe signals, used when DRAM is written to, read from, or refreshed. Fast gives faster performance; and Slow gives more stable performance. This field applies only when synchronous DRAM is installed in the system.

SDRAM Speculative Read

The chipset can "speculate" on a DRAM read address, thus reducing read latencies. The CPU issues a read request containing the data memory address. The DRAM controller receives the request. When this field is Enabled, the controller issues the read command slightly before it has finished decoding the data address.

SDRAM Wait State Control

If necessary, the system designer may insert a wait state into the memory data access cycle.

SDRAM WR Retire Rate

The system designer must select the correct timing for data transfers from the write buffer to memory, according to DRAM specifications.

Security Option

If you have set a password, select whether the password is required every time the System boots, or only when you enter Setup.

Serial Port 1/2 Interrupt

Select between the default PC AT interrupt and no interrupt for COM 1/3 and COM 2/4.

Serial Port 1/2 MIDI

MIDI (musical instrument digital interface) is a standard adopted by the electronic music industry for controlling devices, such as synthesizers and sound cards, that emit music. Select Enabled for the appropriate port if a MIDI device is connected to serial port 1 or serial port 2.

Shadow

Software that resides in a read-only memory (ROM) chip on a device is called firmware. The Award BIOS permits shadowing of firmware such as the system BIOS, video BIOS, and similar operating instructions that come with some expansion peripherals, such as, for example, a SCSI adaptor.

Shadowing copies firmware from ROM into system RAM, where the CPU can read it through the 16-bit or 32-bit DRAM bus. Firmware not shadowed must be read by the system through the 8-bit X-bus. Shadowing improves the performance of the system BIOS and similar ROM firmware for expansion peripherals, but it also reduces the amount of high memory (640 KB to 1 MB) available for loading device drivers, etc.

Enable shadowing into each section of memory separately. Many system designers hardwire shadowing of the system BIOS and eliminate a System BIOS Shadow option.

Video BIOS shadows into memory area C0000-C7FFF. The remaining areas shown on the BIOS Features Setup screen may be occupied by other expansion card firmware. If an expansion peripheral in your system contains ROM-based firmware, you need to know the address range the ROM occupies to shadow it into the correct area of RAM.

Shared VGA Memory Speed

Specify the memory speed of the DRAM allocated for video memory.

Single ALE Enable

Select Enabled to activate a single ALE signal instead of multiple ALEs during a bus conversion cycle.

Single Bit Error Report

If ECC is enabled (see the previous fields), selecting Enabled here tells the system to report an error when a correctable single-bit error occurs.

Sleep Clock

Select Stop Clock or Slow Clock during Sleep mode.

Sleep Timer

After the selected period of system inactivity, all devices except the fixed disk drive and CPU shut off.

Slot 1/2/3/4 Using INT#

Some PCI devices use interrupts to signal that they need to use the PCI bus. Other devices, notably most graphics adapters, do not need interrupt service at all. Each PCI slot can activate up to four interrupts, INT# A, INT# B, INT# C and INT# D. By default, a PCI slot is allowed INT# A. Assigning INT# B has no meaning unless the device in the slot requires two interrupt services rather than just one. Likewise, using INT# C can only mean the device requires three interrupts; and using INT# D, four interrupts. Selecting the default, AUTO, allows the PCI controller to automatically allocate the interrupts.

Slow Refresh Enable

If your system is equipped with slow refresh DRAMs, enabling this setting causes the refresh frequency to be reduced to one-fourth the default speed.

Soft-Off by PWR-BTTN

When Enabled, turning the system off with the on/off button places the system in a very low-power-usage state, with only enough circuitry receiving power to detect power button activity or Resume by Ring activity.

Spread Spectrum Modulated

When the system clock generator pulses, the extreme values of the pulse generate excess EMI. Enabling pulse spectrum spread modulation changes the extreme values from spikes to flat curves, thus reducing EMI. This benefit may in some cases be outweighed by problems with timing-critical devices, such as a clock-sensitive SCSI device. BX

SRAM Back-to-Back

Selecting Enabled reduces the latency between 32-bit data transfers, so data is transferred in 64-bit bursts.

SRAM Read Timing

These SRAM timing numbers are the pattern of cycles the CPU uses to read data from the cache. The system board designer must select the proper combination, depending on the cache size and access speed of the cache SRAMs. Do not reset this option from its default.

SRAM Type

The system controller supports both synchronous and asynchronous cache memory. Set this field to match the type installed in your system.

SRAM Write Timing

If necessary, you can insert a wait state in the SRAM write cycle. The system board designer must select the proper wait state number. If cache memory errors occur, try adding a wait state.

Standby Mode

After the selected period of system inactivity, the fixed disk drive and the video shut off while all other devices still operate at full speed.

Standby Speed (div by)

Select a divisor to reduce the CPU speed during Standby mode to a fraction of the full CPU speed.

Standby Timer Select

Select the timeout period (period of system inactivity) after which the system enters Standby mode. This period should be longer than the period selected for Doze mode.

Standby Timers

After the selected period of inactivity for each subsystem (video, hard drive, peripherals), that subsystem enters Standby mode.

Starting Point of Paging

This value controls the start timing of memory paging operations.

Suspend Mode

After the selected period of system inactivity, all devices except the CPU shut off.

Suspend Mode Option

Select the type of Suspend mode:

POS

Power-on suspend (the CPU and core system remain powered on in a very low-power mode)

Auto

After the period of inactivity selected in the Auto Suspend Timeout field, the system automatically enters STD mode. If STD mode is unavailable, the system enters STR mode.

STD

Save to disk

STR

Suspend to RAM

Suspend Option

This item lets you select a method of global system suspend. Static Suspend, sometimes called Power-on Suspend (POS), leaves the CPU powered on but stops its clock. 0V Suspend, sometimes called Save to Disk (STD) Suspend, saves the state of the entire system to disk and then powers off the system.

Sustained 3T Write

You may enable this field when pipelined burst synchronous SRAM (PBSRAM) cache memory is installed. It enables sustained three-cycle write access for PBSRAM access at 66 or 75 MHz. VP2

Swap Floppy Drive

This field is effective only in systems with two floppy drives. Selecting Enabled assigns physical drive B to logical drive A, and physical drive A to logical drive B.

Switch Function

18. Select the operation of the power button, when pressed:

§ Deturbo. System slows; press a key to return to full power.

§ Break. System enters Suspend mode; press a key to return to full power.

§ Break/Wake. System enters Suspend mode; press the power button again to return to full power.

19. You can choose whether or not to permit your system to enter complete Suspend mode. Suspend mode offers greater power savings, with a correspondingly longer awakening period. SIS5597

SYNC SRAM Support

If synchronous cache memory is installed, this setting allows you to specify whether this memory is the Standard synchronous SRAM or Pipelined SRAM.

Synchronous AT Clock

The AT bus synchronous clock speed is the speed at which the CPU communicates with the AT bus (expansion bus). The speed is measured as a fraction of CLK, the timing signal of the CPU bus. Experiment with setting the bus timing to a lower speed (for example, from CLK/3 to CLK/4) if an installed expansion peripheral has performance problems.

System BIOS Cacheable

Selecting Enabled allows caching of the system BIOS ROM at F0000h-FFFFFh, resulting in better system performance. However, if any program writes to this memory area, a system error may result.

T

Tag Compare Wait States

The tag sample point can be in the first T2 cycle (0 wait states) or second T2 cycle (1 wait state). Tag operation in 0 wait states requires 12-ns SRAM or faster.

Tag Option

Select a 7-bit cache tag RAM with one dirty bit, or an 8-bit tag.

Tag RAM Size

The system uses tag bits to determine the status of data in the cache. Set this field to match the specifications (7 or 8 bits) of the installed tag RAM chip.

Tag/Dirty implement

The system cache controller supports two methods of determining the state of data in the cache. Separate separates the tag signal from the "dirty" signal while Combine combines the two in a single 8- (if 7 bits are selected above) or 9-bit (8 bits selected) signal.

Throttle Duty Cycle

When the system enters Doze mode, the CPU clock runs only part of the time. You may select the percent of time that the clock runs.

Time

The time format is based on the 24-hour military-time clock. For example, 1 p.m. is 13:00:00. Press the right or left arrow key to move to the desired field . Press the PgUp or PgDn key to increment the setting, or type the desired value into the field.

Time
; Timer

Set the time you want the alarm to go off on the days when it is activated. SIS5597

Turbo Read Leadoff

Select Enabled to shorten the leadoff cycles and optimize performance in cacheless, 50-60 MHz, or one-bank EDO DRAM systems.

Turbo VGA (0 WS at A/B)

When Enabled, the VGA memory range of A_0000 to B_0000 uses a special set of performance features. This features has little or no effect during video modes beyond standard VGA, modes most commonly used for high resolution, high color displays associated with Windows, OS/2, UNIX, etc. On the other hand, this memory range is heavily used by games such DOOM.

Turn-Around Insertion

When Enabled, the chipset inserts one extra clock to the turn-around of back-to-back DRAM cycles.

TxD, RxD Active

Consult your IR peripheral documentation to select the correct setting of the TxD and RxD signals.

Typematic Delay (Msec)

When the typematic rate setting is enabled, you can select a typematic delay (the delay before key strokes begin to repeat) of 250, 500, 750 or 1000 milliseconds.

Typematic Rate (Chars/Sec)

When the typematic rate setting is enabled, you can select a typematic rate (the rate at which character repeats when you hold down a key) of 6, 8, 10,12, 15, 20, 24 or 30 characters per second.

Typematic Rate Setting

When Disabled, the following two items (Typematic Rate and Typematic Delay) are irrelevant. Keystrokes repeat at a rate determined by the keyboard controller in your system. When Enabled, you can select a typematic rate and typematic delay.

U

UART 1/2 Duplex Mode

In an infrared port mode, this field appears. Full-duplex mode permits simultaneous two-direction transmission. Half-duplex mode permits transmission in one direction only at a time. Select the value required by the IR device connected to the IR port.

UART 2 Mode

Select an operating mode for the second serial port:

Normal

RS-232C serial port

Standard

RS-232C serial port

IrDA 1.0

Infrared port compliant with IrDA 1.0 specification

IrDA SIR

IrDA-compliant serial infrared port

IrDA MIR

1 MB/sec infrared port

IrDA FIR

Fast Infrared standard

FIR

Fast Infrared standard

MIR 0.57M

0.57-MB/sec infrared port

MIR 1.15M

1.15-MB/sec infrared port

Sharp IR

4-Mb/s data transmission

HPSIR

IrDA-compliant serial infrared port

ASK IR

Amplitude shift keyed infrared port



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