Accessing the CMOS (Cont.)
Bitfields for AWARD configuration bits:
Bit(s) Description (Table C045)
4-7 Screen Colors Used in Setup (see #C046)
3 ??? Default = 0
2 ??? Default = 0
1 ??? Default = 1
0 Enable External Cache
(Table C046)
Values for AWARD setup colors:
0000 Yellow/White on Blue (Default)
0001 Magenta/White on Blue
0010 Yellow/Black on Green
0011 Yellow/Green on Cyan
0100 Black/Yellow on Cyan
0101 Brown/White on Cyan
0110 White/Green on Red
0111 White/White on Red
1000 Green/White on Magenta
1001 Yellow/Red on Magenta
1010 Red/White on Grey
1011 Yellow/White on Grey
1100 Cyan/White on Grey
1101 Cyan/Yellow on Black
1110 White on Black (Monochrome)
1111 Green/Red on Black
See Also: #C045
----------R3C--------------------------------
CMOS 3Ch - PHOENIX - Second user defined hard disk (type 48) Sectors per track
Note: used only when PS/2 style password is NOT in effect.
----------R3C--------------------------------
CMOS 3Ch - AWARD - Boot Configuration Bits
Bitfields for AWARD boot configuration bits:
Bit(s) Description (Table C047)
7 disable virus warning on boot
6,5 ???
4 Quick POST Enabled
3,2 ???
1 Enable Turbo Switch Input
0 0 = Boot from A, then C
1 = Boot from C, then A
----------R3C--------------------------------
CMOS 3Ch - Quadtel HT12 BIOS 03.05.03 - TOTAL MEMORY (low byte)
See Also: CMOS 3Dh"Quadtel"
----------R3D--------------------------------
CMOS 3Dh - AWARD - ???
----------R3D--------------------------------
CMOS 3Dh - Phoenix - ???
Note: bit 3 = base memsize 512K/640K
----------R3D--------------------------------
CMOS 3Dh - Quadtel HT12 BIOS 03.05.03 - TOTAL MEMORY (high byte)
See Also: CMOS 3Ch"Quadtel"
----------R3E--------------------------------
CMOS 3Eh - AMI - Extended CMOS Checksum, High Byte
Note: this checksum covers locations 34h - 3Dh, but is not used by some
later AMI BIOSes
----------R3E--------------------------------
CMOS 3Eh - AWARD - BOOT CONFIGURATION BITS
Bitfields for AWARD boot configuration bits:
Bit(s) Description (Table C048)
7 Shadow Video BIOS at C000h
6,5 ???
4 Swap Floppy Drive
3 ???
2 Don't Halt on Diskette Errors at Boot
1 Don't Halt on Keyboard Errors at Boot
0 Never Halt for any error at Boot
----------R3E--------------------------------
CMOS 3Eh - Quadtel HT12 BIOS 03.05.03 - ???
Bitfields for Quadtel ???:
Bit(s) Description (Table C049)
2 system error occurred ?? (timer/RTC)
0 =0 extended system configuration loaded
=1 checksum error
----------R3E--------------------------------
CMOS 3Eh - Phoenix - SHADOWING CONTROL
Bitfields for Phoenix shadowing control:
Bit(s) Description (Table C050)
7 relocate enable
1 shadow video enable
0 shadow BIOS enable
----------R3F--------------------------------
CMOS 3Fh - AMI - Extended CMOS Checksum, Low Byte
Note: this checksum covers locations 34h - 3Dh, but is not used by some
later AMI BIOSes
----------R3F--------------------------------
CMOS 3Fh - AWARD - ???
---------------------------------------------
End of original 64 CMOS RAM bytes. Many modern chips now contain 128
bytes and the IBM PS/2 has provision for 2k of "Expansion CMOS".
The AMI HI-FLEX description is below. If the chip does have only
64 bytes, addresses will wrap so that requests for bytes 40h-7Fh will
return the same values as 00h-3Fh.
----------R40--------------------------------
CMOS 40h - AMI 1990 Hyundai super-NB368S notebook - POWER-SAVE CONFIGURATION
Bitfields for Hyundai power-save configuration:
Bit(s) Description (Table C051)
7 power save enabled
6-0 HD power save wait, units of 1 minute (0-20)
----------R40--------------------------------
CMOS 40h - AWARD - Motherboard Chipset (SiS 85C501/85C502 shown)
Bitfields for AWARD motherboard chipset:
Bit(s) Description (Table C052)
7-1 ???
0 Automatic Configuration Enabled (Default: 1=enabled)
----------R4055------------------------------
CMOS 40h-55h - AMI WinBIOS - PCI BIOS setup data
----------R41--------------------------------
CMOS 41h - AMI - WAIT STATE CONFIGURATION
Bitfields for AMI wait state configuration:
Bit(s) Description (Table C053)
7-6 IOR/IOW Wait states
5-4 16-bit DMA Wait States
3-2 8-bit DMA Wait States
1 EMR bit
0 DMA Clock Source
----------R4243------------------------------
CMOS 42h-43h - ???
----------R4244------------------------------
CMOS 42h-44h - AWARD - ??? chipset setup ???
----------R44--------------------------------
CMOS 44h - AMI - NMI CONTROL
Bitfields for AMI NMI control:
Bit(s) Description (Table C054)
4 NMI Power Fail Warning
3 NMI Local Bus Timeout
----------R45--------------------------------
CMOS 45h - AMI - BUS DELAYS
Bitfields for AMI bus delays:
Bit(s) Description (Table C055)
7-6 AT Bus 32-Bit Delay
5-4 AT Bus 16-Bit Delay
3-2 AT Bus 8-Bit Delay
1-0 AT Bus I/O Delay
See Also: #C058
----------R45--------------------------------
CMOS 45h - AMI (Saturn) - CACHE TAGS
See Also: CMOS 46h"Saturn"
Bitfields for AMI (Saturn) cache tags:
Bit(s) Description (Table C056)
7 base memory 640K instead of 512K
4-3 external cache tag width
00 8 bits
01 9 bits
10 7 bits
11 7 bits
----------R45--------------------------------
CMOS 45h - AWARD - Motherboard Chipset (SiS 85C501/85C502 shown)
Bitfields for AWARD motherboard chipset:
Bit(s) Description (Table C057)
7 System BIOS Cacheable (Default: 1=enabled)
6 Video BIOS Cacheable (Default: 1=enabled)
5-0 ???
----------R46--------------------------------
CMOS 46h - AMI - BUS WAIT STATES
Bitfields for AMI bus wait states:
Bit(s) Description (Table C058)
7-6 AT Bus 32 Bit Wait States
5-4 AT Bus 16 Bit Wait States
3-2 AT Bus 8 Bit Wait States
1-0 AT Bus Clock Source
See Also: #C055
----------R46--------------------------------
CMOS 46h - AMI (Saturn) - SHADOW RAM CONTROL 1
Bitfields for AMI (Saturn) shadow RAM control 1:
Bit(s) Description (Table C059)
7-6 D000h-D3FFh shadow RAM
00 don't shadow
01 absent
10 shadow
11 reserved
5-4 CC00h-CFFFh shadow RAM (as for D000h-D3FFh)
3-2 C800h-CBFFh shadow RAM (as for D000h-D3FFh)
1-0 C000h-C7FFh shadow RAM (as for D000h-D3FFh)
See Also: #C060
----------R4647------------------------------
CMOS 46h-47h - AWARD - ??? chipset setup ???
----------R47--------------------------------
CMOS 47h - AMI (Saturn) - SHADOW RAM CONTROL 2
Bitfields for AMI (Saturn) shadow RAM control 2:
Bit(s) Description (Table C060)
7-6 DC00h-DFFFh shadow RAM
00 don't shadow
01 absent
10 shadow
11 reserved
5-4 D800h-DBFFh shadow RAM (as for DC00h-DFFFh)
3-2 D400h-D7FFh shadow RAM (as for DC00h-DFFFh)
0 PCI VGA palette snooping
See Also: #C059
----------R4750------------------------------
CMOS 47h-50h - ???
----------R484F------------------------------
CMOS 48h-4Fh - AWARD - ??? unused ??? Defaults to all FFh's.
----------R48--------------------------------
CMOS 48h - AMI (Saturn) - EXTERNAL CACHE
Bitfields for AMI (Saturn) external cache:
Bit(s) Description (Table C061)
5 external cache write-back instead of write-through
----------R49--------------------------------
CMOS 49h - AMI (Saturn) - PERFORMANCE
Bitfields for AMI (Saturn) performance:
Bit(s) Description (Table C062)
1 DRAM enhanced performance mode
0 ISA/DMA enhanced performance mode
See Also: #C063
----------R4A--------------------------------
CMOS 4Ah - AMI (Saturn) - BUS CONFIGURATION
Bitfields for AMI (Saturn) bus configuration:
Bit(s) Description (Table C063)
7 ISA enhanced performance mode
6 ISA bus master installed
5-4 PCI slot IRQ
00 IRQ5
01 IRQ9
10 IRQ15
11 IRQ15
3 PCI on-board SCSI controller enabled
1-0 ISA frame buffer
00 disabled
01 1MB at 15MB
10 2MB at 14MB
11 4MB at 12MB
See Also: #C062
----------R4B--------------------------------
CMOS 4Bh - AMI (Saturn) - ON-BOARD PERIPHERALS
Bitfields for AMI (Saturn) on-board peripherals:
Bit(s) Description (Table C064)
4 onboard FDC enabled
0 onboard IDE enabled
----------R4C--------------------------------
CMOS 4Ch - AMI (Saturn) - PARALLEL PORT