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-=-=-=-=-=-=-
CMOS-Memory Map Release 61 Last change 16jul00
Copyright (c) 1989-1999,2000 Ralf Brown
Originally compiled from multiple sources by Padgett Peterson
<padgett@tccslr.dnet.mmc.com>.
No guarantees of any kind.
Copyrights/Trademarks belong to whoever they may belong to.
Found: Algorithm used by IBM in calculating CRC checksums for PS/2
(see bytes 32h-33h). Complex (recursive part is 12 lines of
assembly) and not yet validated for every model.
--------!---Note-----------------------------
Background
The CMOS (complementary metal oxide semiconductor) memory is actually
a 64 or 128 byte battery-backed RAM memory module that is a part of the
system clock chip. Some IBM PS/2 models have the capability for a
2k (2048 byte) CMOS ROM Extension.
First used with clock-calender cards for the IBM PC-XT, when the PC/AT
(Advanced Technology) was introduced in 1985, the Motorola MC146818
became a part of the motherboard. Since the clock only uses fourteen of
the RAM bytes, the rest are available for storing system configuration data.
Interestingly, the original IBM-PC/AT (Advanced Technology) standard for
the region 10h-3Fh is nearly universal with one notable exception: The
IBM PS/2 systems deviate considerably (Note: AMSTRAD 8086 machines were
among the first to actively use the CMOS memory available and since they
- predate* the AT, do not follow the AT standard).
This is just another example of how IBM created a standard, lost control
of it, tried to replace it, failed and lost market share in the process.
Originally, the IBM PC/AT only made use of a small portion of CMOS memory
and was defined in the IBM PC/AT Technical Reference Manual, specifically
bytes 10h, 12h, 14h-18h, 2Eh-33h. The balance was left undefined but was
quickly appropriated by various BIOS manufacturers for such user-selectable
options such as wait states, clock speeds, initial boot drive selection, and
password storage.
Later, as CMOS memory requirements grew, newer clock chips with 128
bytes of RAM came into use. However the fact remains that once the AT
standard was established, only IBM has tried to change the definitions
of that first description.
Accessing the CMOS
The CMOS memory exists outside of the normal address space and cannot
contain directly executable code. It is reachable through IN and OUT
commands at port number 70h (112d) and 71h (113d). To read a CMOS byte,
an OUT to port 70h is executed with the address of the byte to be read and
an IN from port 71h will then retrieve the requested information. The
following BASIC fragment will read 128 CMOS bytes and print them to the
screen in 8 rows of 16 values.
The CMOS RAM space has an upper limit of 128 bytes because of the structure
of port 70: only bits 0-6 are used for addressing, bit 7 is used to
enable (0) or disable (1) Non-Maskable Interrupts (NMI) and explains why
IBM uses 80h OR <address> to read/write data & follows with a "throw-away"
call.
Note that if the CMOS only has 64 bytes available, addressing will
generally wrap and addresses from 40h-7Fh will mirror 00h-3Fh. Output will
be hexadecimal.
10 CLS
20 FOR i = 0 TO &H7F
30 OUT &H70, i
40 PRINT USING "\ \"; HEX$(INP(&H71));
50 NEXT i
60 PRINT " "
Note: where not otherwise noted, all data points are expressed as BYTES
these are eight bit values and are read from MSB to LSB e.g.
0000 0000 0101 1010 binary would be written as 5Ah
7654 3210 where only some bits are used this is represented with
Xs e.g bits 5-3 would be shown as 00xx x000
Note: the entries for AMI WinBIOS also apply to AMIBIOS with core dates of
12/15/95 or later
Newer BIOSes have two checksums in the CMOS RAM, the second one covering
bytes 40h through 7Ch (or 7Eh). Unfortunately, the second checksum is at
a different location in different BIOSes. The following code from
Agapov Vasiliy Pavlovich <arhfond@online.ru> (28 Aug 1996) is designed to
find the location of the second checksum byte on *any* BIOS (successfully
tested on various versions of AMI and AWARD BIOSes).
Agapov's instructions for use:
> Before starting this code make sure to load the 128 bytes of CMOS data
> to the buffer at CMOS_DATA and assume DS as data area segment register.
START: CALL WHAT_CMOS
JC NO_SECOND_CHS
; Checksum location is in word at CHECKS_ADDRESS
NO_SECOND_CHS:
; There's no second checksum in this CMOS
END:
;******************************* SUBS **********************************
WHAT_CMOS: MOV SI,OFFSET CMOS_DATA+40H
MOV DI,OFFSET CMOS_DATA+7EH
CALL FIND_CMOS_CHS
JNC END_WCMOS
MOV SI,OFFSET CMOS_DATA+41H
MOV DI,OFFSET CMOS_DATA+7EH
CALL FIND_CMOS_CHS
END_WCMOS: RET
FIND_CMOS_CHS: XOR DX,DX
MOV AX,DX
FIND_CMOS_C1: LODSB ; GET BYTE
ADD DX,AX
CMP SI,OFFSET CMOS_DATA+7CH ; ADDRESS OF CHECKSUM ?
JB FIND_CMOS_C1
XCHG DH,DL
CMP DX,[SI] ; CHECKSUM FOUND ?
JZ END_FCMOS
XCHG DH,DL
CMP SI,DI
JB FIND_CMOS_C1
STC
RET
END_FCMOS: MOV [CHECKS_ADDRESS],SI ; SAVE CHECKSUM POSITION
CLC
RET
- ******************************* DATA *******************************
CHECKS_ADDRESS DW 0
CMOS_DATA DB 128 DUP (?)
--------!---Note-----------------------------
Organization of CMOS Memory - Clock
00h-0Eh is defined by the clock hardware and all must follow it. Other
manufacturers generally follow the same format as specified for the
region 10h - 2Fh. Some also follow the IBM format for 30h-33h but not all
(Zenith in particular is different).
The first fourteen bytes are dedicated to the MC146818 chip clock functions
and consist of ten read/write data registers and four status registers, two
of which are read/write and two of which are read only.
The format of the ten clock data registers (bytes 00h-09h) is:
----------R00--------------------------------
CMOS 00h - RTC - SECONDS
Desc: (BCD 00-59, Hex 00-3B)
Note: Bit 7 is read only
SeeAlso: CMOS 01h,CMOS 02h,CMOS 04h
----------R01--------------------------------
CMOS 01h - RTC - SECOND ALARM
Desc: (BCD 00-59, Hex 00-3B; "don't care" if C0-FF)
SeeAlso: CMOS 00h,CMOS 03h,CMOS 05h,CMOS 7Dh
----------R02--------------------------------
CMOS 02h - RTC - MINUTES
Desc: (BCD 00-59, Hex 00-3B)
SeeAlso: CMOS 00h,CMOS 03h,CMOS 04h
----------R03--------------------------------
CMOS 03h - RTC - MINUTE ALARM
Desc: (BCD 00-59, Hex 00-3B; "don't care" if C0-FF))
SeeAlso: CMOS 00h,CMOS 02h,CMOS 05h,CMOS 7Dh,CMOS 7Eh"AMD-645"
----------R04--------------------------------
CMOS 04h - RTC - HOURS
Desc: (BCD 00-23, Hex 00-17 if 24 hr mode)
(BCD 01-12, Hex 01-0C if 12 hr am)
(BCD 81-92. Hex 81-8C if 12 hr pm)
SeeAlso: CMOS 00h,CMOS 02h,CMOS 05h
----------R05--------------------------------
CMOS 05h - RTC - HOUR ALARM
Desc: (same as hours; "don't care" if C0-FF))
SeeAlso: CMOS 01h,CMOS 03h,CMOS 04h
----------R06--------------------------------
CMOS 06h - RTC - DAY OF WEEK
Desc: (01-07 Sunday=1)
SeeAlso: CMOS 07h,CMOS 08h,CMOS 09h
----------R07--------------------------------
CMOS 07h - RTC - DATE OF MONTH
Desc: (BCD 01-31, Hex 01-1F)
SeeAlso: CMOS 06h,CMOS 08h,CMOS 09h
----------R08--------------------------------
CMOS 08h - RTC - MONTH
Desc: (BCD 01-12, Hex 01-0C)
SeeAlso: CMOS 06h,CMOS 07h,CMOS 09h
----------R09--------------------------------
CMOS 09h - RTC - YEAR
Desc: (BCD 00-99, Hex 00-63)
Notes: BCD/Hex selection depends on Bit 2 of register B (0Bh)
12/24 Hr selection depends on Bit 1 of register B (0Bh)
Alarm will trigger when contents of all three Alarm byte registers
match their companions.
SeeAlso: CMOS 06h,CMOS 07h,CMOS 08h
The following is the on-chip status register information.
----------R0A--------------------------------
CMOS 0Ah - RTC - STATUS REGISTER A (read/write) (usu 26h)
Bitfields for Real-Time Clock status register A:
Bit(s) Description (Table C0001)
7 =1 time update cycle in progress, data ouputs undefined
(bit 7 is read only)
6-4 22 stage divider
010 = 32768 Hz time base (default)
3-0 rate selection bits for interrupt
0000 none
0011 122 microseconds (minimum)
1111 500 milliseconds
0110 976.562 microseconds (default 1024 Hz)
Notes: some operating systems seem to change the CMOS clock rate to slower
values for unknown purposes. Since on older ATs the clock rate does
not get restored after a cold boot, this may slow down disk
operations for example under PC DOS which depends on the clock rate.
If IBMBIO.COM finds a model byte FCh (sub-models 00h, 01h, 02h, 03h,
or 06h) during init, it resets the clock rate to the default value
(00100110b).
SeeAlso: #C0002,#C0003,#C0004
----------R0B--------------------------------
CMOS 0Bh - RTC - STATUS REGISTER B (read/write)
Bitfields for Real-Time Clock status register B:
Bit(s) Description (Table C0002)
7 enable clock setting by freezing updates
6 enable periodic interrupt
5 enable alarm interrupt
4 enable update-ended interrupt
3 enable square wave output
2 Data Mode - 0: BCD, 1: Binary
1 24/12 hour selection - 1 enables 24 hour mode
0 Daylight Savings Enable
=1 enables automatic switching to/from DST in April and October
Notes: some operating systems seem to change the CMOS clock rate to slower
values for unknown purposes. Since on older ATs the clock rate does
not get restored after a cold boot, this may slow down disk
operations for example under PC DOS which depends on the clock rate.
If IBMBIO.COM finds a model byte FCh (sub-models 00h, 01h, 02h, 03h,
or 06h) during init, it resets the clock rate to the default value
(00100110b).
SeeAlso: #C0001,#C0003,#C0004
----------R0C--------------------------------
CMOS 0Ch - RTC - STATUS REGISTER C (Read only)
Bitfields for Real-Time Clock status register C:
Bit(s) Description (Table C0003)
7 Interrupt request flag
=1 when any or all of bits 6-4 are 1 and appropriate enables
(Register B) are set to 1. Generates IRQ 8 when triggered.
6 Periodic Interrupt flag
5 Alarm Interrupt flag
4 Update-Ended Interrupt Flag
3-0 unused
SeeAlso: #C0001,#C0002,#C0004
----------R0D--------------------------------
CMOS 0Dh - RTC - STATUS REGISTER D (read only)
Bitfields for Real-Time Clock status register D:
Bit(s) Description (Table C0004)
7 Valid RAM - 1 indicates battery power good, 0 if dead or disconnected.
6-0 unused (0)
--------!---Note-----------------------------
Organization of CMOS Memory - non-Clock
The last two bytes in the first hexadecimal decade (hexade ?) were not
specified in the PC/AT but may have the following use on some systems:
----------R0E--------------------------------
CMOS 0Eh - IBM PS/2 - DIAGNOSTIC STATUS BYTE
Bitfields for IBM PS/2 diagnostic status byte:
Bit(s) Description (Table C0005)
7 indicates clock has lost power
6 incorrect checksum
5 equipment configuration is incorrect
(power-on check requires that at least one floppy be installed)
4 error in memory size
3 controller or disk drive failed initialization
2 time is invalid
1 installed adaptors do not match configuration
0 time-out while reading adaptor ID
Note: Compaq machines with dual hard disk controllers support at least bits
7 and 6
----------R0E13------------------------------
CMOS 0Eh-13h - AMSTRAD - TIME AND DATE MACHINE LAST USED
----------R0F--------------------------------
CMOS 0Fh - IBM - RESET CODE (IBM PS/2 "Shutdown Status Byte")
(Table C0006)
Values for Reset Code / Shutdown Status Byte:
00h-03h perform power-on reset
00h software reset or unexpected reset
01h reset after memory size check in real/virtual mode
(or: chip set initialization for real mode reentry)
02h reset after successful memory test in real/virtual mode
03h reset after failed memory test in real/virtual mode
04h INT 19h reboot
05h flush keyboard (issue EOI) and jump via 40h:0067h
06h reset (after successful test in virtual mode)
(or: jump via 40h:0067h without EOI)
07h reset (after failed test in virtual mode)
08h used by POST during protected-mode RAM test (return to POST)
09h used for INT 15/87h (block move) support
0Ah resume execution by jump via 40h:0067h
0Bh resume execution via IRET via 40h:0067h
0Ch resume execution via RETF via 40h:0067h
0Dh-FFh perform power-on reset
--------!---Note-----------------------------
The second group of values extends from address 10h to 2Dh. The word at
2Eh-2Fh is a byte-wise summation of the values in these bytes. Most BIOSes
will generate a CMOS Checksum error if this value is invalid however many
programs ignore the checksum and report the apparent value. The current
version of MSD reports my XT as having 20+ MB of extended memory.
Where a definiton appears universal, no identification is made. Where
the definition is thought to be specific to a manufacturer/model (AMI,
AMSTRAD, IBM AT, IBM PS/2) the identification is enclosed in parens. The
AMSTAD definitions appear to relate to 8088/8086 (PC and PC/XT class)
mchines only. AT class machines appear to adhere to IBM PC/AT fornat.
----------R10--------------------------------
CMOS 10h - IBM - FLOPPY DRIVE TYPE
Note: a PC having a 5 1/4 1.2 Mb A: drive and a 1.44 Mb B: drive will
have a value of 24h in byte 10h. With a single 1.44 drive: 40h.
Bitfields for floppy drives A/B types:
Bit(s) Description (Table C0007)
7-4 first floppy disk drive type (see #C0008)
3-0 second floppy disk drive type (see #C0008)
(Table C0008)
Values for floppy drive type:
00h no drive
01h 360 KB 5.25 Drive
02h 1.2 MB 5.25 Drive - note: not listed in PS/2 technical manual
03h 720 KB 3.5 Drive
04h 1.44 MB 3.5 Drive
05h 2.88 MB 3.5 drive
06h-0Fh unused
SeeAlso: #C0007
----------R11--------------------------------
CMOS 11h - IBM PS/2 - FIRST FIXED DISK DRIVE TYPE BYTE (00-FFh)
Note: if IBM ESDI or SCSI drive controller is used, CMOS drive type will be
zero (00 - no drive) and INT 13h will be directed to controller ROM.
----------R11--------------------------------
CMOS 11h - older AMI Hi-Flex BIOS - KEYBOARD TYPEMATIC DATA
Bitfields for AMI Hi-Flex BIOS keyboard typematic data:
Bit(s) Description (Table C0009)
7 enable Typematic
6-5 Typematic Delay (wait before begin repeating)
00b 250 ms
01b 500 ms
10b 750 ms
11b 100 ms
4-0 Typematic Rate (char/sec)
00000b - 30.0 01000b - 15.9 10000b - 7.5 11000b - 3.7
00001b - 26.7 01001b - 13.3 10001b - 6.7 11001b - 3.3
00010b - 24.0 01010b - 12.0 10010b - 6.0 11010b - 3.0
00011b - 21.8 01011b - 10.9 10011b - 5.5 11011b - 2.7
00100b - 20.0 01100b - 10.0 10100b - 5.0 11100b - 2.5
00101b - 18.5 01101b - 9.2 10101b - 4.6 11101b - 2.3
00110b - 17.1 01110b - 8.6 10110b - 4.3 11110b - 2.1
00111b - 16.0 01111b - 8.0 10111b - 4.0 11111b - 2.0
----------R11--------------------------------
CMOS 11h - AMI - ADVANCED SETUP OPTIONS
Bitfields for AMI advanced setup options:
Bit(s) Description (Table C0010)
7 mouse enabled
6 test memory above 1 megabyte
5 generate clicks during memory test
4 enable memory parity check
3 display key for Setup while booting
2 store user-defined disk data at top of memory instead of 0030h:0000h
1 request F1 keypress on boot error
----------R11--------------------------------
CMOS 11h - AMI WinBIOS - BOOT OPTIONS
SeeAlso: CMOS 13h"AMI"
Bitfields for AMI WinBIOS boot options:
Bit(s) Description (Table C0011)
7 systems boots with high CPU speed
6 memory test above 1MB enabled
5 memory test tick sound enabled
4 floppy drive seek at boot enabled
3 "Hit <Del>" message enabled
2 BIOS extended RAM area takes 1K at top of memory instead of 30h:0000h
1 wait for F1 key on error
0 NumLock enabled at boot
----------R11--------------------------------
CMOS 11h - AWARD - CONFIGURATION BITS
SeeAlso: CMOS 5Eh"AWARD"
Bitfields for AWARD configuration bits:
Bit(s) Description (Table C0012)
7 NumLock ON at reboot
6 IDE Block Mode enabled
5 ???
4 Shadow ROM BIOS at CC00-CFFF
3 Shadow ROM BIOS at C800-CBFF
2 ???
1 BIOS Password Enabled (supervisor)
0 0 = Password controls BIOS Setup Only
1 = Password required to enter System
SeeAlso: #C0083
Code snippet by Jens Rehsack:
FUNCTION CalcPossiblePassword( PasswordValue: WORD ): STRING[8];
VAR
I : BYTE;
C : CHAR;
S : STRING[8];
BEGIN
I := 0;
WHILE PasswordValue <> 0 DO
BEGIN
Inc( I );
IF $263 > PasswordValue THEN
BEGIN
IF $80 > PasswordValue THEN
S[I] := CHAR( PasswordValue )
ELSE IF $B0 > PasswordValue THEN
S[I] := CHAR( PasswordValue AND $77 )
ELSE IF $11D > PasswordValue THEN
S[I] := CHAR( $30 OR ( PasswordValue AND $0F ) )
ELSE IF $114 > PasswordValue THEN
BEGIN
S[I] := CHAR( $64 OR ( PasswordValue AND $0F ) );
IF '0' > S[I] THEN
S[I] := CHAR( BYTE( S[I] ) + 8 );
END ELSE IF $1C2 > PasswordValue THEN
S[I] := CHAR( $70 OR ( PasswordValue AND $03 ) )
ELSE IF $1E4 > PasswordValue THEN
S[I] := CHAR( $30 OR ( PasswordValue AND $03 ) )
ELSE
BEGIN
S[I] := CHAR( $70 OR ( PasswordValue AND $0F ) );
IF 'z' < S[I] THEN
S[I] := CHAR( BYTE( S[I] ) - 8 );
END;
END ELSE
S[I] := CHAR( $30 OR ( PasswordValue AND $3 ) );
PasswordValue := ( PasswordValue - BYTE( S[I] ) ) SHR 2;
END;
S[0] := CHAR( I );
PasswordValue := I SHR 1;
WHILE PasswordValue < I DO
BEGIN {this is to do because award starts calculating with the last letter}
C := S[BYTE( S[0] ) - I + 1];
S[BYTE( S[0] ) - I + 1] := S[I];
S[I] := C;
Dec( I );
END;
CalcPossiblePassword := S;
END;
"Okay, the algorithms based on the knowlege, that the award-bios' 4.50 and 4.51
but not (seems to) with earlier versions stores only the last 2 bit of every
character typed in..."
int CalcPasswordCRC( char pw[8] ): word
{
register int i = 8;
register unsigned w = 0;
while( i-- )
w |= ( unsigned( pw[i] ) & 0x3 ) << ( i * 2 );
return w;
}
----------R11--------------------------------
CMOS 11h - Quadtel HT12 BIOS 03.05.03 - CONFIGURATION BITS
Bitfields for Quadtel HT12 configuration bits:
Bit(s) Description (Table C0013)
7 640K RAM present
6 extension type (=CPU's Machine Status Word)
3-2 NumLock state at boot time
00 Auto
01 NumLock on
10 Numlock off
0 384K RAM relocated to top of memory
----------R12--------------------------------
CMOS 12h - IBM - HARD DISK DATA
Notes: A PC with a single type 2 (20 Mb ST-225) hard disk will have 20h in
byte 12h
some PCs utilizing external disk controller ROMs will use type 0 to
disable ROM BIOS (e.g. Zenith 248 with Plus HardCard).
Bitfields for IBM hard disk data:
Bit(s) Description (Table C0014)
7-4 First Hard Disk Drive
00 No drive
01-0Eh Hard drive Type 1-14
0Fh Hard Disk Type 16-255
(actual Hard Drive Type is in CMOS RAM 19h)
3-0 Second Hard Disk Drive Type
(same as first except extrnded type will be found in 1Ah).
----------R12--------------------------------
CMOS 12h - IBM PS/2 - SECOND FIXED DISK DRIVE TYPE (00-FFh)
SeeAlso: CMOS 11h"IBM PS/2"
----------R13--------------------------------
CMOS 13h - AMI Hi-Flex BIOS - ADVANCED SETUP OPTIONS
SeeAlso: CMOS 11h"WinBIOS"
Bitfields for AMI Hi-Flex BIOS advanced setup options:
Bit(s) Description (Table C0015)
7 Mouse Enabled (1 = On)
6 Test Memory above 1 MB (1 = On)
5 Memory Test Tick Sound (1 = On)
4 Memory Parity Error Check (1 = On)
3 Press <Esc> to Disable Memory Test (1 = On)
2 User-Defined Hard Disk (1 = Type 47 data area at address 0:300h)
1 Wait for <F1> Message if Error (1 = On)
0 Turn Num Lock On at boot (1 = On)
----------R13--------------------------------
CMOS 13h - AMI WinBIOS - PERIPHERAL OPTIONS
Bitfields for AMI WinBIOS peripheral options:
Bit(s) Description (Table C0016)
7-5 typematic rate
000-111 = 6,8,10,12,15,20,24,30 cps
4 numeric processor test enabled
----------R13--------------------------------
CMOS 13h - PS/2 MCA - INTERNAL POST OPERATIONS
Bitfields for PS/2 MCA internal POST operations:
Bit(s) Description (Table C0017)
7 POST sets VGA pel information
6 RTC battery OK
5 invoke ROM BASIC from POST
4 POST sets typematic to 30cps/250ms delay instead of 10.9cps/500ms
3-2 unused or unknown
1 network password installed
0 power-on password installed
----------R13--------------------------------
CMOS 13h - AWARD - Configuration Bits
Bitfields for AWARD configuration bits:
Bit(s) Description (Table C0018)
7 set keyboard typematic rate
4-6 keyboard repeat rate
000 = 6 cps
001 = 8 cps
010 = 10 cps
011 = 12 cps
100 = 15 cps
101 = 20 cps
110 = 24 cps
111 = 30 cps
2-3 keyboard typematic delay
00 = 250 Msec
01 = 500 Msec
10 = 750 Msec
11 = 1000 Msec
1 ???
0 boot up floppy seek
----------R14--------------------------------
CMOS 14h - IBM - EQUIPMENT BYTE
Bitfields for IBM equipment byte:
Bit(s) Description (Table C0019)
7-6 number of floppy drives (system must have at least one)
00b 1 Drive
01b 2 Drives
10b ??? 3 Drives
11b ??? 4 Drives
5-4 monitor type
00b Not CGA or MDA (observed for EGA & VGA)
01b 40x25 CGA
10b 80x25 CGA
11b MDA (Monochrome)
3 display enabled (turned off to enable boot of rackmount)
2 keyboard enabled (turn off to enable boot of rackmount)
1 math coprocessor installed
0 floppy drive installed (turned off for rackmount boot)
----------R14--------------------------------
CMOS 14h - AMSTRAD - BYTE user RAM checksum
Desc: LSB of sum of all user bytes should be AAh
----------R15--------------------------------
CMOS 15h - IBM - BASE MEMORY IN KB (low byte)
----------R1516------------------------------
CMOS 15h-16h - AMSTRAD - Enter key scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 74h
Note: default: 1C0Dh - emulates Return key
SeeAlso: INT 09,CMOS 17h"AMSTRAD"
----------R16--------------------------------
CMOS 16h - IBM - BASE MEMORY IN KB (high byte)
Note: The value in 15h-16h should be the same as in 0:413h and that
returned by INT 12h. A PC having 640k (280h) of conventional
memory will return 80h in byte 15h and 02h in byte 16h.
----------R17--------------------------------
CMOS 17h - IBM - EXTENDED MEMORY IN KB (low byte)
----------R1718------------------------------
CMOS 17h-18h - AMSTRAD - Forward delete key scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 70h
Note: default: 2207h - emulates ^G (bell/beep)
SeeAlso: INT 09,CMOS 15h"AMSTRAD",CMOS 19h"AMSTRAD"
----------R18--------------------------------
CMOS 18h - IBM - EXTENDED MEMORY IN KB (high byte)
Notes: some systems will only accommodate 15 MB extended (16 MB total)
Format is the same as in 15h-16h
----------R19--------------------------------
CMOS 19h - IBM - FIRST EXTENDED HARD DISK DRIVE TYPE
Note: not in original AT specification but now nearly universally used
except for PS/2.
(Table C0020)
Values for extended hard disk drive type:
00-0Fh unused (would not require extension. Note: this has the effect of
making type 0Fh (15d) unavailable.
10h-FFh First Extended Hard Drive Type 16d-255d
Note: For most manufacturers the last drive type (typically either 47d or 49d)
is "user defined" and parameters are stored elsewhere in the CMOS.
----------R19--------------------------------
CMOS 19h - MCA - SLOT 0 ADAPTER CARD ID
----------R19--------------------------------
CMOS 19h - AMI - ???
Bitfields for AMI location 19h:
Bit(s) Description (Table C0021)
3-0 ???
7-4 ???
----------R191A------------------------------
CMOS 19h-1Ah - AMSTRAD - Joystick fire button 1 scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 77h
Note: default: FFFFh - (no translation)
SeeAlso: INT 09,CMOS 17h"AMSTRAD",CMOS 1Bh"AMSTRAD"
----------R1A--------------------------------
CMOS 1Ah - SECOND EXTENDED HARD DISK DRIVE TYPE
SeeAlso: CMOS 19h"IBM",#C0020
----------R1A--------------------------------
CMOS 1Ah - MCA - SLOT 0 ADAPTER CARD ID
----------R1B--------------------------------
CMOS 1Bh - MCA - SLOT 1 ADAPTER CARD ID
----------R1B--------------------------------
CMOS 1Bh - AMI - First Hard Disk (type 47) user defined: # of Cylinders, LSB
Note: this byte is also supported by Compaq machines with dual hard disk
controllers
SeeAlso: MEM F000h:FFE8h
----------R1B1C------------------------------
CMOS 1Bh-1Ch - AMSTRAD - Joystick fire button 2 scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 78h
Note: default: FFFFh - (no translation)
SeeAlso: INT 09,CMOS 19h"AMSTRAD",CMOS 1Dh"AMSTRAD"
----------R1B--------------------------------
CMOS 1Bh - PHOENIX - LSB of Word to 82335 RC1 roll compare register
----------R1B--------------------------------
CMOS 1Bh - AWARD - CONFIGURATION BITS
Bitfields for AWARD shadow RAM configuration bits:
Bit(s) Description (Table C0022)
7-4 ???
3 Shadow ROM BIOS at DC00-DFFF
2 shadow " " " D800-DBFF
1 shadow " " " D400-D7FF
0 shadow " " " D000-D3FF
----------R1C--------------------------------
CMOS 1Ch - MCA - SLOT 1 ADAPTER CARD ID
----------R1C--------------------------------
CMOS 1Ch - AMI - First Hard Disk user defined: # of Cylinders, High Byte
----------R1C--------------------------------
CMOS 1Ch - PHOENIX - MSB of Word to 82335 RC1 roll compare register
--------y-R1C--------------------------------
CMOS 1Ch,1Dh - AWARD - Password
Note: Stored as a checksum using the following algorithm:
initialize 16-bit checksum to zero
for each ASCII character between 32 (space) and 127 (DEL) in the
password, add character to checksum, then rotate left two bits
store low byte of result in 1Ch and high byte in 1Dh (for user
password, use locations 4Dh and 4Eh instead)
SeeAlso: CMOS 4Dh"AWARD"
----------R1D--------------------------------
CMOS 1Dh - MCA - SLOT 2 ADAPTER CARD ID
----------R1D--------------------------------
CMOS 1Dh - AMI - First Hard Disk user defined: Number of Heads
----------R1D--------------------------------
CMOS 1Dh - AMSTRAD - mouse button 1 scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 7Dh
Note: default: FFFFh - (no translation)
SeeAlso: INT 09,CMOS 1Bh"AMSTRAD",CMOS 1Fh"AMSTRAD"
----------R1D--------------------------------
CMOS 1Dh - Zenith Z-200 monitor - BOOT DRIVE SELECTION
Bitfields for Zenith Z-200 boot drive selection:
Bit(s) Description (Table C0023)
6-5 (0xx0 0000)
00 - MFM Monitor
01 - First floppy drive (A:)
10 - First fixed disk (C:)
11 - First floppy drive (A:). If not there then First fixed disk (C:)
(this is the default).
----------R1D--------------------------------
CMOS 1Dh - PHOENIX - LSB of Word to 82335 RC2 roll compare register
--------y-R1D--------------------------------
CMOS 1Dh - AWARD - MSB of password checksum (see byte 1Ch)
----------R1D--------------------------------
CMOS 1Dh - Quadtel HT 12 BIOS - first user def. drive: # of cylinders low byte
----------R1E--------------------------------
CMOS 1Eh - MCA - SLOT 2 ADAPTER CARD ID
----------R1E--------------------------------
CMOS 1Eh - AMI - First Hard Disk user defined: WPC-low
Desc: Write Precompensation Cylinder, Low Byte, for first user-defined hard
disk
----------R1E--------------------------------
CMOS 1Eh - PHOENIX - MSB of Word to 82335 RC2 roll compare register
----------R1E--------------------------------
CMOS 1Eh - AWARD - 2nd Hard Disk user defined: # of Cylinders Low Byte
----------R1E--------------------------------
CMOS 1Eh - Quadtel HT 12 BIOS - FIRST USER DEFINED DRIVE
Bitfields for Quadtel HT-12 user-defined drive heads/cylinders:
Bit(s) Description (Table C0024)
7-4 number of heads
3-0 number of cylinders (MSB)
----------R1F--------------------------------
CMOS 1Fh - MCA - SLOT 3 ADAPTER CARD ID
----------R1F--------------------------------
CMOS 1Fh - AMI - First Hard Disk user defined: WPC-high
Desc: Write Precompensation Cylinder, high byte, for first user-defined
hard disk
----------R1F20------------------------------
CMOS 1Fh-20h - AMSTRAD - mouse button 2 scancode/ASCII code
Size: WORD
Desc: specify the BIOS keycode for keyboard scancode 7Eh
Note: default: FFFFh - (no translation)
SeeAlso: INT 09,CMOS 1Dh"AMSTRAD"
----------R1F--------------------------------
CMOS 1Fh - AWARD - 2nd Hard Disk user defined (type 48): # of Cylinders High
----------R1F--------------------------------
CMOS 1Fh - Quadtel HT 12 BIOS - first user def. drive: WPC-low
Desc: Write Precompensation Cylinder, low byte, for first user-defined
hard disk
----------R20--------------------------------
CMOS 20h - MCA - SLOT 3 ADAPTER CARD ID
----------R20--------------------------------
CMOS 20h - AMI - First Hard Disk user defined: Control Byte
Bitfields for AMI user-defined hard disk control byte:
Bit(s) Description (Table C0025)
7-6 no retries (1)
5 bad sector map at last cylinder+1
4 unused (0)
3 more than 8 heads
2-0 unused (0)
----------R20--------------------------------
CMOS 20h - AMI WinBIOS - First Hard Disk user defined: Landing Zone, Low Byte
----------R20--------------------------------
CMOS 20h - PHOENIX - First user defined hard disk (type 48) Cylinders LSB
----------R20--------------------------------
CMOS 20h - AWARD - 2nd Hard Disk user defined (type 48): Number of Heads
----------R20--------------------------------
CMOS 20h - Quadtel HT 12 BIOS - FIRST USER DEFINED DRIVE
SeeAlso: CMOS 26h"Quadtel"
Bitfields for Quadtel landing zone/write-precompensation:
Bit(s) Description (Table C0026)
7-4 landing zone MSB
3-0 write precom. cyl. MSB
----------R21--------------------------------
CMOS 21h - MCA - Programmable Option Select configuration byte 2
----------R21--------------------------------
CMOS 21h - AMI - First Hard Disk user defined: Landing Zone, Low Byte
----------R21--------------------------------
CMOS 21h - AMI WinBIOS - First Hard Disk user defined: Landing Zone, High Byte
----------R21--------------------------------
CMOS 21h - AMSTRAD - MOUSE X SCALING FACTOR
Note: default: 0Ah
----------R21--------------------------------
CMOS 21h - PHOENIX - First user defined hard disk (type 48) Cylinders MSB
----------R21--------------------------------
CMOS 21h - AWARD - 2nd Hard Disk user defined (type 48): Write Precomp Low Byte
----------R21--------------------------------
CMOS 21h - Quadtel HT 12 BIOS - first user def. drive: landing zone low byte
----------R22--------------------------------
CMOS 22h - MCA - Programmable Option Select configuration byte 3
----------R22--------------------------------
CMOS 22h - AMI - First Hard Disk user defined: Landing Zone, High Byte
----------R22--------------------------------
CMOS 22h - AMI WinBIOS - First Hard Disk user defined: # of Sectors per track
----------R22--------------------------------
CMOS 22h - AMSTRAD - MOUSE Y SCALING FACTOR
Note: default: 0Ah
----------R22--------------------------------
CMOS 22h - PHOENIX - First user defined hard disk (type 48) of Heads
----------R22--------------------------------
CMOS 22h - AWARD - 2nd Hard Disk user defined (type 48): Write Precomp High Byte
----------R22--------------------------------
CMOS 22h - Quadtel HT 12 BIOS - first user def. drive: sectors per track
----------R23--------------------------------
CMOS 23h - MCA - Programmable Option Select configuration byte 4
----------R23--------------------------------
CMOS 23h - AMI - First Hard Disk user defined: # of Sectors per track
----------R23--------------------------------
CMOS 23h - AMI WinBIOS - Second Hard Disk user defined: # Cylinders, Low Byte
----------R23--------------------------------
CMOS 23h - AMSTRAD - INITIAL VDU MODE AND DRIVE COUNT
Note: default: 20h
Bitfields for Amstrad initial VDU mode/drive count:
Bit(s) Description (Table C0027)
7 enables extended serial flow control (NB this is buggy)
6 set if two floppy drives installed
5-4 (from Amstrad 1640 tech ref)
00 Internal video adapter
01 CGA card added; 40 x 25 mode
10 CGA card added; 80 x 25 mode
11 mono card added; 80 x 25 mode
----------R23--------------------------------
CMOS 23h - PHOENIX - First user defined hard disk (type 48) Write Precomp. LSB
----------R23--------------------------------
CMOS 23h - AWARD - 2nd Hard Disk user defined (type 48): Landing Zone Low Byte
----------R23--------------------------------
CMOS 23h - Quadtel HT 12 BIOS - second user def. drive: # of cylinders low byte
----------R24--------------------------------
CMOS 24h - MCA - Programmable Option Select configuration byte 5
----------R24--------------------------------
CMOS 24h - AMI - Second Hard Disk user defined: # Cylinders, Low Byte
----------R24--------------------------------
CMOS 24h - AMI WinBIOS - Second Hard Disk user defined: # Cylinders, High Byte
----------R24--------------------------------
CMOS 24h - AMSTRAD - INITIAL VDU CHARACTER ATTRIBUTE
Note: default: 7h
----------R24--------------------------------
CMOS 24h - PHOENIX - First user defined hard disk (type 48) Write Precomp. MSB
----------R24--------------------------------
CMOS 24h - AWARD - 2nd Hard Disk user defined (type 48): Landing Zone High Byte
----------R24--------------------------------
CMOS 24h - Quadtel HT 12 BIOS - SECOND USER DEFINED DRIVE
SeeAlso: CMOS 1Eh"Quadtel",#C0024
----------R25--------------------------------
CMOS 25h - AMI - Second Hard Disk user defined: # of Cylinders, High Byte
----------R25--------------------------------
CMOS 25h - AMI WinBIOS - Second Hard Disk user defined: Number of Heads
----------R25--------------------------------
CMOS 25h - AMSTRAD - size of RAM disk in 2K blocks
Note: default: 0 - only used by the RAMDISK software supplied.
----------R25--------------------------------
CMOS 25h - PHOENIX - First user defined hard disk (type 48) Parking zone LSB
----------R25--------------------------------
CMOS 25h - AWARD - 2nd Hard Disk user defined (type 48): Sectors per Track
----------R25--------------------------------
CMOS 25h - Quadtel HT 12 BIOS - second user def. drive: WPC-low
Desc: Write Precompensation Cylinder, low byte
----------R25--------------------------------
CMOS 25h - COMPAQ 386 - MACHINE CONFIGURATION
SeeAlso: MEM F000h:FFE0h
Bitfields for Compaq machine configuration:
Bit(s) Description (Table C0099)
3 soft drive???
----------R26--------------------------------
CMOS 26h - AMI - Second Hard Disk user defined: Number of Heads
----------R26--------------------------------
CMOS 26h - AMI WinBIOS - Second Hard Disk user defined: WPC-low
Desc: Write Precompensation Cylinder, Low Byte
----------R26--------------------------------
CMOS 26h - AMSTRAD - INITIAL SYSTEM UART SETUP BYTE
Note: default: E3h - format as for Int 14h fn 0
----------R26--------------------------------
CMOS 26h - PHOENIX - First user defined hard disk (type 48) Parking zone MSB
----------R26--------------------------------
CMOS 26h - AWARD - 1st Hard Disk user defined (type 49): # Cylinders, Low Byte
----------R26--------------------------------
CMOS 26h - Quadtel HT 12 BIOS - SECOND USER DEFINED DRIVE
SeeAlso: CMOS 20h"Quadtel",#C0026
----------R27--------------------------------
CMOS 27h - AMI - Second Hard Disk user defined: WPC-low
Desc: Write Precompensation Cylinder, Low Byte
----------R27--------------------------------
CMOS 27h - AMI WinBIOS - Second Hard Disk user defined: WPC-high
Desc: Write Precompensation Cylinder, High Byte
----------R27--------------------------------
CMOS 27h - AMSTRAD - INITIAL EXTERNAL UART SETUP BYTE
Note: default: E3h - format as for Int 14h fn 0
----------R27--------------------------------
CMOS 27h - PHOENIX - First user defined hard disk (type 48) Sectors per track
----------R27--------------------------------
CMOS 27h - AWARD - 1st Hard Disk user defined (type 49): # Cylinders, High Byte
----------R27--------------------------------
CMOS 27h - Quadtel HT 12 BIOS - SECOND USER DEF. DRIVE: landing zone low byte
----------R28--------------------------------
CMOS 28h - AMI - Second Hard Disk user defined: WPC-high
Desc: Write Precompensation Cylinder, High Byte
----------R28--------------------------------
CMOS 28h - AMI WinBIOS - Second Hard Disk user defined: Landing Zone, Low Byte
----------R28--------------------------------
CMOS 28h - HP Vectra - checksum over bytes 29h-2Dh
----------R28--------------------------------
CMOS 28h - AWARD - 1st Hard Disk user defined (type 49): Number of Heads
----------R28--------------------------------
CMOS 28h - Quadtel HT 12 BIOS - second user def. drive: sectors per track
----------R283F------------------------------
CMOS 28h-3Fh - AMSTRAD - user applications default: zeroes
----------R29--------------------------------
CMOS 29h - AMI - Second Hard Disk user defined: Control Byte
Note: 80h if # of heads is equal or greater than 8
----------R29--------------------------------
CMOS 29h - AMI WinBIOS - Second Hard Disk user defined: Landing Zone, High Byte
----------R29--------------------------------
CMOS 29h - PHOENIX - LSB word to Intel 82335 CC0 compare register
----------R29--------------------------------
CMOS 29h - AWARD - 1st Hard Disk user defined (type 49): Write Precomp Low Byte
----------R29--------------------------------
CMOS 29h - HP Vectra - OFFICIALLY RESERVED "CMOS_HPCONFIG"
Bitfields for HP Vectra CMOS_HPCONFIG:
Bit(s) Description (Table C0028)
7 include byte 2Ch in checksum (default = 0)
6 select second ROM video adapter as primary (default = 0)
5-1 reserved
0 manufacturing test enabled
----------R2A--------------------------------
CMOS 2Ah - AMI - Second Hard Disk user defined: Landing Zone, Low Byte
----------R2A--------------------------------
CMOS 2Ah - AMI WinBIOS - Second Hard Disk user defined: # of Sectors per track
----------R2A--------------------------------
CMOS 2Ah - HP Vectra - OFFICIALLY RESERVED
----------R2A--------------------------------
CMOS 2Ah - PHOENIX - MSB word to Intel 82335 CC0 compare register
----------R2A--------------------------------
CMOS 2Ah - AWARD - 1st Hard Disk user defined (type 49): Write Precomp High
----------R2B--------------------------------
CMOS 2Bh - AMI - Second Hard Disk user defined: Landing Zone, High Byte
----------R2B--------------------------------
CMOS 2Bh - AMI WinBIOS - IDE and shadowing control
Bitfields for AMI WinBIOS IDE/shadowing control:
Bit(s) Description (Table C0029)
7 LBA mode enabled
6 IDE block mode enabled
5 32-bit transfer enabled
4 unused
3 shadowing of DC00h enabled
2 shadowing of D800h enabled
1 shadowing of D400h enabled
0 shadowing of D000h enabled
SeeAlso: #C0030
----------R2B--------------------------------
CMOS 2Bh - HP Vectra - OFFICIALLY RESERVED
----------R2B--------------------------------
CMOS 2Bh - PHOENIX - LSB word to Intel 82335 CC1 compare register
----------R2B--------------------------------
CMOS 2Bh - AWARD - 1st Hard Disk user defined (type 49): Landing Zone Low Byte
----------R2C--------------------------------
CMOS 2Ch - AMI - Second Hard Disk user defined: # of Sectors per track
----------R2C--------------------------------
CMOS 2Ch - AMI WinBIOS - CACHE CONTROL
Bitfields for AMI WinBIOS cache control:
Bit(s) Description (Table C0030)
7 external RAM cache enabled
6 internal RAM cache enabled
5 shadowing of E000h enabled
4 shadowing of CC00h enabled
3 shadowing of C800h enabled
2 shadowing of C400h (video ROM) enabled
1 shadowing of C000h (video ROM) enabled
0 shadowing of system BIOS (F000h, 64K) enabled
SeeAlso: #C0029
----------R2C--------------------------------
CMOS 2Ch - HP Vectra - OFFICIALLY RESERVED
----------R2C--------------------------------
CMOS 2Ch - COMPAQ - NumLock CONTROL
Bitfields for Compaq NumLock control:
Bit(s) Description (Table C0031)
6 0 - numlock OFF on boot, 1 - numlock ON at boot
----------R2C--------------------------------
CMOS 2Ch - PHOENIX - MSB word to Intel 82335 CC1 compare register
----------R2C--------------------------------
CMOS 2Ch - AWARD - 1st Hard Disk user defined (type 49): Landing Zone High Byte
----------R2D--------------------------------
CMOS 2Dh - AMI Hi-Flex BIOS - CONFIGURATION OPTIONS
Bitfields for AMI Hi-Flex BIOS configuration options:
Bit(s) Description (Table C0032)
7 Weitek Installed
6 Floppy Drive Seek - turn off for fast boot
5 Boot Order
0 - Drive C:, then A:
1 - Drive A:, then C:
4 Boot Speed (0 - Low; 1 - High)
3 External Cache Enable (1 = On)
2 Internal Cache Enable (1 = On)
1 Use Fast Gate A20 after boot (1 = On)
0 Turbo Switch (1 = On)
----------R2D--------------------------------
CMOS 2Dh - AMI WinBIOS - flags
Bitfields for AMI WinBIOS flags:
Bit(s) Description (Table C0033)
7 Weitek Installed
6 bootsector virus protection enabled
5 mouse enabled
4 password checking (0 setup, 1 always)
3 parity error check enabled
2-1 boot order (00 = C:A:, 01 = A:C:)
0 turbo switch enabled
----------R2D--------------------------------
CMOS 2Dh - HP Vectra - OFFICIALLY RESERVED
----------R2D--------------------------------
CMOS 2Dh - PHOENIX - ???
Note: checks for values AAh or CCh
----------R2D--------------------------------
CMOS 2Dh - AWARD - 1st Hard Disk user defined (type 49): Sectors per Track
----------R2E--------------------------------
CMOS 2Eh - IBM - Standard CMOS Checksum, High Byte
----------R2F--------------------------------
CMOS 2Fh - IBM - Standard CMOS Checksum, Low Byte
2Eh and 2Fh are as defined by the original IBM PC/AT specification and
represent a byte-wise additive sum of the values in locations 10h-2Dh only,
00h-0Fh and 30h-33h are not included. This definition is used by most
clone manufacturers including AMI, Compaq, Tandon, NEC, and Zenith. The
IBM PS/2 line does not follow this standard with the range 19h-31h being
undefined. On the original HP Vectra, this checksum only covers locations
10h to 20h, with a separate checksum for bytes 29h-2Ch (see offset 28h).
----------R30--------------------------------
CMOS 30h - IBM - EXTENDED MEMORY IN KB (low byte)
SeeAlso: CMOS 17h"IBM",CMOS 31h
----------R31--------------------------------
CMOS 31h - IBM - EXTENDED MEMORY IN KB (high byte)
(this appears to mirror the value in bytes 17h-18h.)
SeeAlso: CMOS 18h"IBM",CMOS 30h
----------R32--------------------------------
CMOS 32h - IBM - CENTURY BYTE (BCD value for the century - currently 19h)
SeeAlso: CMOS 7Fh
----------R32--------------------------------
CMOS 32h - IBM PS2 - CONFIGURATION CRC LOW BYTE
Desc: CRC for range 10h-31h
SeeAlso: CMOS 33h"PS/2"
----------R33--------------------------------
CMOS 33h - IBM - INFORMATION FLAG
Bitfields for IBM information flag:
Bit(s) Description (Table C0034)
7 128K ??? believe this indicates the presence of the special 128k
memory expansion board for the AT to boost the "stock" 512k
to 640k - all machines surveyed have this bit set)
6-0 ???
----------R33--------------------------------
CMOS 33h - IBM PS/2 - CONFIGURATION CRC HIGH BYTE (see entry for 32h)
SeeAlso: CMOS 32h"PS/2"
----------R33--------------------------------
CMOS 33h - PHOENIX - Bit 4 (000x 0000) bit 4 from Intel CPU register CR0
----------R33--------------------------------
CMOS 33h - AMI WinBIOS - INFORMATION FLAGS
Bitfields for AMI WinBIOS information flags:
Bit(s) Description (Table C0035)
7 IBM-defined top 128K present
6-4 CPU internal clock frequency
000-011 = 25, 33, 40, 50 MHz
100 = 60/66 MHz
101 = 75 MHz
110 = 80 MHz
111 = 90/100 MHz
2-1 CPU internal clock multiplier
00-11 = 1,2,3,4
0 FlashROM programming enabled (Ctrl-Home pressed at power on)
Note: this location is not included in any CMOS checksum fields
----------R33--------------------------------
CMOS 33h - Quadtel HT12 BIOS 03.05.03 - INFORMATION FLAGS
Bitfields for Quadtel HT12 information flags:
Bit(s) Description (Table C0036)
7 640K RAM present
6 extension type (=CPU's Machine Status Word)
1 print welcome message
----------R34--------------------------------
CMOS 34h - AMI - SHADOWING & BOOT PASSWORD
SeeAlso: CMOS 35h"AMI"
Bitfields for AMI shadowing control 1:
Bit(s) Description (Table C0037)
7-6 password selection
00b Disable
10b Reserved
01b Set
11b Boot
5 C8000h Shadow ROM (Bit 1 = On)
4 CC000h Shadow ROM (Bit 1 = On)
3 D0000h Shadow ROM (Bit 1 = On)
2 D4000h Shadow ROM (Bit 1 = On)
1 D8000h Shadow ROM (Bit 1 = On)
0 DC000h Shadow ROM (Bit 1 = On)
SeeAlso: #C0038
----------R34--------------------------------
CMOS 34h - AMI - EXTENDED MEMORY >16M (low byte)
Note: this and the following byte contain the total extended memory in 64K
blocks
SeeAlso: CMOS 35h"AMI"
----------R34--------------------------------
CMOS 34h - (AMI WinBIOS) system-specific information (bits 3-1)
----------R343A------------------------------
CMOS 34h-3Ah - (AWARD) ??? unused ??? Defaults to all FFh's.
----------R35--------------------------------
CMOS 35h - AMI - EXTENDED MEMORY >16M (high byte)
Note: this and the previous byte contain the total extended memory in 64K
blocks
SeeAlso: CMOS 34h"AMI"
----------R35--------------------------------
CMOS 35h - AMI - SHADOWING CONTROL 2
SeeAlso: CMOS 34"AMI"
Bitfields for AMI shadowing control 2:
Bit(s) Description (Table C0038)
7 E0000h Shadow ROM (Bit 1 = On)
6 E4000h Shadow ROM (Bit 1 = On)
5 E8000h Shadow ROM (Bit 1 = On)
4 EC000h Shadow ROM (Bit 1 = On)
3 F0000h Shadow ROM (Bit 1 = On)
2 C0000h Shadow ROM (Bit 1 = On)
1 C4000h Shadow ROM (Bit 1 = On)
0 reserved
SeeAlso: #C0037
----------R35--------------------------------
CMOS 35h - AMI WinBIOS - EXTENDED MEMORY SIZE IN 64K BLOCKS (low byte)
SeeAlso: CMOS 36h"AMI WinBIOS"
----------R35--------------------------------
CMOS 35h - PHOENIX - Second user defined hard disk (type 48) Cylinders LSB
Note: used only when PS/2 style password is NOT in effect
----------R35--------------------------------
CMOS 35h - AMI 1990 Hyundai super-NB368S notebook
Bitfields for Hyundai configuration:
Bit(s) Description (Table C0039)
3-1 shadowing
000 shadow disabled
011 video BIOS shadowed
100 main BIOS shadowed
111 both
0 coprocessor enabled
----------R36--------------------------------
CMOS 36h - PHOENIX - Second user defined hard disk (type 48) Cylinders MSB
Note: used only when PS/2 style password is NOT in effect.
----------R36--------------------------------
CMOS 36h - AWARD - IDE control
Bitfields for AWARD IDE control:
Bit(s) Description (Table C0040)
6 IDE 32-bit transfer mode
----------R36--------------------------------
CMOS 36h - AMI - ???
Bitfields for AMI ???:
Bit(s) Description (Table C0041)
1-0 ???
3-2 ???
----------R36--------------------------------
CMOS 36h - AMI WinBIOS - EXTENDED MEMORY SIZE IN 64K BLOCKS (high byte)
----------R36--------------------------------
CMOS 36h - AMI 1990 Hyundai super-NB368S notebook - CPU/VIDEO CONFIGURATION
Bitfields for Hyundai CPU/video control:
Bit(s) Description (Table C0042)
7 =1 LCD, 0 CRT at boot time
6 =1 reversed, 0 normal video mode
5 =1 external, 0 internal keyboard
4-3 CPU speed
00 high
01 medium
10 low
2-1 harddisk vendor 1,2,3,4
0 relocation enabled
----------R36--------------------------------
CMOS 36h - Quadtel HT12 BIOS 03.05.03 - EXTENDED MEMORY (low byte)
----------R37--------------------------------
CMOS 37h - IBM PS/2 - DATE CENTURY BYTE
----------R37--------------------------------
CMOS 37h - PHOENIX - Second user defined hard disk (type 48) # of heads
NOTE: used only when PS/2 style password is NOT in effect.
----------R37--------------------------------
CMOS 37h - AMI Hi-Flex BIOS - ???
Bitfields for AMI Hi-Flex BIOS location 37h:
Bit(s) Description (Table C0043)
7 ???
----------R37--------------------------------
CMOS 37h - AMI WinBIOS - SETUP COLORS, PASSWORD SEED
Bitfields for AMI WinBIOS setup colors and password seed:
Bit(s) Description (Table C0044)
7-4 password seed
3-0 WinBIOS/AMIBIOS setup color options
----------R37--------------------------------
CMOS 37h - Quadtel HT12 BIOS 03.05.03 - EXTENDED MEMORY (high byte)
--------y-R373A------------------------------
CMOS 37h-3Ah - AMI 1990 Hyundai super-NB368S notebook - PASSWORD
Desc: encoded password, max 4 bytes.
----------R38--------------------------------
CMOS 38h - PHOENIX - Second user defined hard disk (type 48) Write Precomp. LSB
Note: used only when PS/2 style password is NOT in effect.
--------y-R383D------------------------------
CMOS 38h-3Dh - AMI - Encrypted Password
--------y-R383F------------------------------
CMOS 38h-3Fh - ??? IBM PS/2 - Encrypted Password
Note: Initialized to 00h in all bytes. Will accept from 1-7 scan codes.
----------R39--------------------------------
CMOS 39h - PHOENIX - Second user defined hard disk (type 48) Write Precomp. MSB
Note: used only when PS/2 style password is NOT in effect.
----------R3A--------------------------------
CMOS 3Ah - PHOENIX - Second user defined hard disk (type 48) Parking Zone LSB
Note: used only when PS/2 style password is NOT in effect.
----------R3B--------------------------------
CMOS 3Bh - PHOENIX - Second user defined hard disk (type 48) Parking Zone MSB
Note: used only when PS/2 style password is NOT in effect.
----------R3B--------------------------------
CMOS 3Bh - AWARD - CONFIGURATION BITS
Bitfields for AWARD configuration bits:
Bit(s) Description (Table C0045)
4-7 Screen Colors Used in Setup (see #C0046)
3-2 translation used for first disk
00 normal, 01 LBA, 10 Large, 11 Auto
1 ??? Default = 1
0 Enable External Cache
(Table C0046)
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
SeeAlso: #C0045
----------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 C0047)
7 disable virus warning on boot
6,5 ???
4 Quick POST Enabled
3,2 translation used for second disk
00 normal, 01 LBA, 10 Large, 11 Auto
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)
SeeAlso: 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)
SeeAlso: 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 C0048)
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 C0049)
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 C0050)
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.
--------p-R40--------------------------------
CMOS 40h - AMI 1990 Hyundai super-NB368S notebook - POWER-SAVE CONFIGURATION
Bitfields for Hyundai power-save configuration:
Bit(s) Description (Table C0051)
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 C0052)
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 C0053)
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 C0054)
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 C0055)
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
SeeAlso: #C0058
----------R45--------------------------------
CMOS 45h - AMI (Saturn) - CACHE TAGS
SeeAlso: CMOS 46h"Saturn"
Bitfields for AMI (Saturn) cache tags:
Bit(s) Description (Table C0056)
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 C0057)
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 C0058)
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
SeeAlso: #C0055
----------R46--------------------------------
CMOS 46h - AMI (Saturn) - SHADOW RAM CONTROL 1
Bitfields for AMI (Saturn) shadow RAM control 1:
Bit(s) Description (Table C0059)
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)
SeeAlso: #C0060
----------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 C0060)
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
SeeAlso: #C0059
----------R4750------------------------------
CMOS 47h-50h - ???
----------R484F------------------------------
CMOS 48h-4Fh - AWARD - ??? unused ??? Defaults to all FFh's.
--------y-R484F------------------------------
CMOS 48h-4Fh - PhoenixBIOS A486 v1.01.E - USER PASSWORD
Desc: stores scan-codes for the password in the first seven bytes, and the
low byte of the password checksum in the eighth byte
SeeAlso: CMOS 50h"A486 v1.01.E"
----------R48--------------------------------
CMOS 48h - AMI (Saturn) - EXTERNAL CACHE
Bitfields for AMI (Saturn) external cache:
Bit(s) Description (Table C0061)
5 external cache write-back instead of write-through
----------R49--------------------------------
CMOS 49h - AMI (Saturn) - PERFORMANCE
Bitfields for AMI (Saturn) performance:
Bit(s) Description (Table C0062)
1 DRAM enhanced performance mode
0 ISA/DMA enhanced performance mode
SeeAlso: #C0063
----------R4A--------------------------------
CMOS 4Ah - AMI (Saturn) - BUS CONFIGURATION
Bitfields for AMI (Saturn) bus configuration:
Bit(s) Description (Table C0063)
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
SeeAlso: #C0062
----------R4B--------------------------------
CMOS 4Bh - AMI (Saturn) - ON-BOARD PERIPHERALS
Bitfields for AMI (Saturn) on-board peripherals:
Bit(s) Description (Table C0064)
4 onboard FDC enabled
0 onboard IDE enabled
----------R4C--------------------------------
CMOS 4Ch - AMI (Saturn) - PARALLEL PORT
Bitfields for AMI (Saturn) parallel port:
Bit(s) Description (Table C0065)
4 IRQ active high
3 parallel port extended mode
1-0 parallel port address
----------R4C--------------------------------
CMOS 4Ch - AMI (PicoPower) - CLOCK SPEEDS
Bitfields for AMI (PicoPower) clock speeds:
Bit(s) Description (Table C0066)
7-6 back-to-back I/O delay
00 none
01 1 SYSCLK
10 2 SYSCLKs
11 3 SYSCLKs
5-3 Turbo clock select
001 CLK2IN/3
010 CLK2IN/4
011 CLK2IN/5
100 CLK2IN/6
101 CLK2IN/7
110 CLK2IN/8
111 CLK2IN/9
2-0 SYSCLK select (same as for Turbo clock select)
----------R4D--------------------------------
CMOS 4Dh - AMI (Saturn) - RESERVED
----------R4D--------------------------------
CMOS 4Dh - AMI (PicoPower) - MIDDLE BIOS
Note: Middle BIOS is enabled if bit 1 set
--------y-R4D--------------------------------
CMOS 4Dh - AWARD - USER PASSWORD
SeeAlso: CMOS 4Eh"AWARD",CMOS 1Ch"AWARD"
----------R4E--------------------------------
CMOS 4Eh - AMI (Saturn) - SERIAL PORT
Bitfields for AMI (Saturn) serial port:
Bit(s) Description (Table C0067)
7-5 serial port 1
4-2 serial port 2
0 manual programming mode
----------R4E--------------------------------
CMOS 4Eh - AMI (PicoPower) - TURBO BUS VIDEO
Bitfields for AMI (PicoPower) Turbo Bus video:
Bit(s) Description (Table C0068)
2 memory enabled
1 I/O enabled
--------y-R4E--------------------------------
CMOS 4Eh - AWARD - USER PASSWORD
SeeAlso: CMOS 4Dh"AWARD",CMOS 1Ch"AWARD"
----------R50--------------------------------
CMOS 50h - AWARD - PCI Bus Slot 1 Latency Timer 0-255 (default: 0)
--------y-R5057------------------------------
CMOS 50h-57h - PhoenixBIOS A486 v1.01.E - ADMIN PASSWORD
Desc: stores scan-codes for the password in the first seven bytes, and the
low byte of the password checksum in the eighth byte
SeeAlso: CMOS 48h"A486 v1.01.E"
----------R51--------------------------------
CMOS 51h - AMI - MEMORY ACCESS CONTROL
Bitfields for AMI memory access control:
Bit(s) Description (Table C0069)
7 Bank 0/1 RAS Precharge
6 Bank 0/1 Access Wait States
3-2 Bank 0/1 Wait States
----------R51--------------------------------
CMOS 51h - AWARD - PCI Bus Setup
Bitfields for AWARD PCI bus setup:
Bit(s) Description (Table C0070)
7 PIRQ0# Interrupt Triggering
0 = Edge Sensitive,
1 = Level Sensitive
6-2 ??? Default: all 1's
0-1 Slot 1 IRQ Setup
00 = A-PIRQ0 (Default)
01 = B-PIRQ1
10 = C-PIRQ2
11 = D-PIRQ3
----------R52--------------------------------
CMOS 52h - ???
----------R52--------------------------------
CMOS 52h - AWARD - PCI Bus Slot 2 Latency Timer 0-255 (default: 0)
----------R53--------------------------------
CMOS 53h - AMI - MEMORY ACCESS CONTROL
Bitfields for AMI memory access control:
Bit(s) Description (Table C0071)
7 Bank 2/3 RAS Precharge
6 Bank 2/3 Access Wait States
3-2 Bank 2/3 Wait States
----------R53--------------------------------
CMOS 53h - AWARD - PCI Bus Setup
Bitfields for AWARD PCI bus setup:
Bit(s) Description (Table C0072)
7 PIRQ1# Interrupt Triggering
0 = Edge Sensitive,
1 = Level Sensitive
6-2 ??? Default: all 1's
0-1 Slot 2 IRQ Setup
00 = A-PIRQ1 (Default)
01 = B-PIRQ2
10 = C-PIRQ3
11 = D-PIRQ0
--------p-R53--------------------------------
CMOS 53h - AWARD v4.51PG APM - APM FUNCTION CONFIGURATION FOR ATX POWER SUPPLY
SeeAlso: CMOS 54h"v4.51PG"
Bitfields for AWARD v4.51PG ATX Power Supply Configuration #1:
Bit(s) Description (Table C0073)
7 power button override enabled
6-2 ???
1 VGA is active monitor
0 ???
SeeAlso: #C0074
----------R547F------------------------------
CMOS 54h-7Fh - ???
----------R54--------------------------------
CMOS 54h - AWARD - PCI Bus Slot 3 Latency Timer 0-255 (default: 0)
--------p-R54--------------------------------
CMOS 54h - AWARD v4.51PG APM - APM FUNCTION CONFIGURATION FOR ATX POWER SUPPLY
SeeAlso: CMOS 53h"v4.51PG"
Bitfields for AWARD v4.51PG ATX Power Supply Configuration #2:
Bit(s) Description (Table C0074)
7-2 ???
1 enable Resume on Ring
0 enable Resume on Alarm
SeeAlso: #C0073
----------R55--------------------------------
CMOS 55h - AWARD - PCI Bus Setup
Bitfields for AWARD PCI bus setup:
Bit(s) Description (Table C0075)
7 PIRQ2# Interrupt Triggering
0 = Edge Sensitive,
1 = Level Sensitive
6-2 ??? Default: all 1's
0-1 Slot 3 IRQ Setup
00 = A-PIRQ2 (Default)
01 = B-PIRQ3
10 = C-PIRQ0
11 = D-PIRQ1
--------p-R55--------------------------------
CMOS 55h - AWARD v4.51PG - APM - POWER-ON DAY OF MONTH (Resume by Alarm)
Note: value is binary, rather than BCD as for most calendar functions
SeeAlso: CMOS 56h"v4.51PG",CMOS 57h"v4.51PG"
----------R56--------------------------------
CMOS 56h - AWARD - ??? reserved for PCI Bus Slot 4 Latency Timer ???
--------p-R56--------------------------------
CMOS 56h - AWARD v4.51PG - APM - POWER-ON HOUR (Resume by Alarm)
Note: value is binary, rather than BCD as for most calendar functions
SeeAlso: CMOS 55h"v4.51PG",CMOS 57h"v4.51PG"
----------R57--------------------------------
CMOS 57h - AWARD - PCI Bus Setup
Bitfields for AWARD PCI bus setup:
Bit(s) Description (Table C0076)
7 PIRQ3# Interrupt Triggering
0 = Edge Sensitive,
1 = Level Sensitive
6-0 ???not used Default: all 1's
--------p-R57--------------------------------
CMOS 57h - AWARD v4.51PG - APM - POWER-ON MINUTE (Resume by Alarm)
Note: value is binary, rather than BCD as for most calendar functions
SeeAlso: CMOS 56h"v4.51PG",CMOS 58h"v4.51PG"
----------R58--------------------------------
CMOS 58h - AWARD - ??? reserved for PCI Bus Slot 5 Latency Timer ???
Bitfields for AWARD PCI bus slot 5 latency timer:
Bit(s) Description (Table C0077)
3 onboard CMD IDE Mode 3
--------p-R58--------------------------------
CMOS 58h - AWARD v4.51PG - APM - POWER-ON SECOND (Resume by Alarm)
Note: value is binary, rather than BCD as for most calendar functions
SeeAlso: CMOS 55h"v4.51PG",CMOS 57h"v4.51PG"
----------R59--------------------------------
CMOS 59h - AWARD - ??? reserved for PCI Bus Setup ???
----------R5A--------------------------------
CMOS 5Ah - AWARD - PCI Bus IRQ Setup 1
Bitfields for AWARD PCI bus IRQ setup 1:
Bit(s) Description (Table C0078)
4-7 PIRQ1# Interrupt Line (0=none, Bh=IRQ11, etc)
0-3 PIRQ0# Interrupt Line " " "
----------R5B--------------------------------
CMOS 5Bh - AWARD - PCI Bus IRQ Setup 2
Bitfields for AWARD PCI bus IRQ setup 2:
Bit(s) Description (Table C0079)
4-7 PIRQ3# Interrupt Line (0=none, Bh=IRQ11, etc)
0-3 PIRQ2# Interrupt Line " " "
----------R5C--------------------------------
CMOS 5Ch - AMI (PicoPower) - LOW-SPEED CLOCK
Bitfields for AMI (PicoPower) low-speed clock select:
Bit(s) Description (Table C0080)
2-0 low-speed clock divisor
000 /1
001 /2
010 /4
----------R5C5F------------------------------
CMOS 5Ch-5Fh - AWARD - ??? unused ???
Note: Defaults to all FFh's.
--------p-R5D--------------------------------
CMOS 5Dh - AMI (PicoPower) - DOZE MODE
Bitfields for AMI (PicoPower) doze mode control:
Bit(s) Description (Table C0081)
7 APM enabled
6-4 doze mode CPU clock speed (see #C0082)
3 hotkey setup enabled
2-0 "sleep mode" CPU CLK speed (see #C0082)
SeeAlso: #C0084
(Table C0082)
Values for AMI (PicoPower) CPU clock speeds:
000 MAX
001 MAX/2
010 MAX/4
011 MAX/8
100 MAX/16
101 MAX/32
110 MAX/64
SeeAlso: #C0081,#C0084
----------R5E--------------------------------
CMOS 5Eh - AMI 1990 Hyundai super-NB368S notebook - ???
00h when values from bios defaults
34h when values from power up defaults
----------R5E--------------------------------
CMOS 5Eh - AWARD v4.50G - ?
SeeAlso: CMOS 5Fh"AWARD"
Bitfields for AWARD register 5Eh:
Bit(s) Description (Table C0083)
0 user password enabled
SeeAlso: #C0012
--------p-R5E--------------------------------
CMOS 5Eh - AMI (PicoPower) - CPU SPEEDS
Bitfields for AMI (PicoPower) CPU speeds:
Bit(s) Description (Table C0084)
7 suspend warning beeps enabled
6-4 "full on" CPU CLK speed
000 MAX
001 MAX/2
010 MAX/4
011 MAX/8
1-0 power management mode
00 disabled
01 Auto
10 enabled
SeeAlso: #C0081
--------p-R5F--------------------------------
CMOS 5Fh - AMI (PicoPower) - POWER MANAGEMENT TIMEOUTS
Bitfields for AMI (PicoPower) power management timeouts:
Bit(s) Description (Table C0085)
7 enable battery-low beeps
5-3 SUSPEND timeout
000 disabled
001 5 minutes
010 10 minutes
011 15 minutes
100 20 minutes
101 30 minutes
110 40 minutes
111 60 minutes
2-0 DOZE timeout
000 disabled
100 1 second
101 4 seconds
110 8 seconds
111 16 seconds
SeeAlso: #C0087
--------y-R5F--------------------------------
CMOS 5Fh - AWARD v4.50G - USER PASSWORD CHECKSUM
SeeAlso: CMOS 5Eh"AWARD"
--------p-R60--------------------------------
CMOS 60h - AWARD - POWER MANAGEMENT
Bitfields for AWARD power management:
Bit(s) Description (Table C0086)
7 ???
6 Video Off Method
1 = V/H SYNC + Blank (default)
0 = Blank Screen
4,5 Video Off Option
00 = Always On (default)
01 = Suspend -> Off
10 = Suspend, Standby -> Off
11 = All Modes -> Off
3 PM Control by APM (1=Yes)
2 ???
1,0 Power Management Setup
00 User Defined
01 Disabled (default)
10 Minimum Power Savings (40 Minutes for all events)
11 Maximum Power Savings (20 Seconds for all events)
--------p-R60--------------------------------
CMOS 60h - AMI (PicoPower) - SLEEP TIMEOUT
Bitfields for AMI (PicoPower) sleep timeout:
Bit(s) Description (Table C0087)
5-3 SLEEP timeout
000 disabled
001 1 minute
010 2 minutes
011 3 minutes
100 4 minutes
101 6 minutes
110 8 minutes
111 12 minutes
SeeAlso: #C0085,#C0089
----------R6077------------------------------
CMOS 60h-77h - AMI WinBIOS - PCI chipset-specific setup information
--------p-R61--------------------------------
CMOS 61h - AWARD - POWER MANAGEMENT
Bitfields for AWARD power management:
Bit(s) Description (Table C0088)
7 PM Event on HDD Ports Activity (1=enable)
6 PM Event on LPT Port Activity (1=enable)
5 PM Event on COM Port Activity (1=enable)
4 HDD Power Down on Suspend
0-3 HDD Power Down Time
0 Disabled
1-15 Time in Minutes
----------R62--------------------------------
CMOS 62h - AMI 1990 Hyundai super-NB368S notebook - ???
FFh when values from bios defaults
FEh when values from power up defaults
----------R62--------------------------------
CMOS 62h - AMI (Neptune) - number of last PCI bus in system
SeeAlso: INT 1A/AX=B101h
--------p-R62--------------------------------
CMOS 62h - AMI (PicoPower) - HARD-DISK POWERDOWN
Bitfields for AMI (PicoPower) hard-disk powerdown timeout:
Bit(s) Description (Table C0089)
3-0 hard-disk timeout in minutes (0000 = disabled)
SeeAlso: #C0087
--------p-R62--------------------------------
CMOS 62h - AWARD - POWER MANAGEMENT
Bitfields for AWARD power management:
Bit(s) Description (Table C0090)
7-4 Standby Mode Setting (for User Defined)
0 Disabled
1 20 Seconds
2 1 Minute
3 5 Minutes
4 10 Minutes
5 15 Minutes
6 20 Minutes
7 30 Minutes
8 40 Minutes
0-3 Doze Mode Setting (for User Defined)
(See Standby Mode above)
----------R62--------------------------------
CMOS 62h - AWARD v4.51pg - BIT FLAGS
Bitfields for AWARD v4.51pg CMOS 62h:
Bit(s) Description (Table C0091)
0 user password is enabled
--------p-R63--------------------------------
CMOS 63h - AWARD - POWER MANAGEMENT
Bitfields for AWARD power management:
Bit(s) Description (Table C0092)
7 Disable PM Event on IRQ3 Activity (COM2) (1=disable)
6 PM Event on VGA Activity (1=enable)
5 ??? (Defaults to 1)
4 PM Event on PCI/ISA Master Activity (1=enable)
0-3 Suspend Mode Setting (for User Defined)
(See Standby Mode above)
--------p-R63--------------------------------
CMOS 63h - AMI (PicoPower) - BATTERY-LOW ACTIONS
Bitfields for AMI (PicoPower) battery-low actions:
Bit(s) Description (Table C0093)
5-3 battery-very-low action
000 MAX
001 MAX/2
010 MAX/4
011 MAX/8
100 MAX/16
101 MAX/32
110 MAX/64
111 suspend
2-0 battery-low action (same as battery-very-low action)
----------R64--------------------------------
CMOS 64h - AMI 1990 Hyundai super-NB368S notebook - ???
--------p-R64--------------------------------
CMOS 64h - AMI (PicoPower) - BATTERY POWER
Bitfields for AMI (PicoPower) battery power:
Bit(s) Description (Table C0094)
6 extended battery debounce enabled
4-3 resume with modem ring
00 disabled
01 one ring
10 two rings
11 three rings
2 365SL power on during suspend
1-0 suspend-mode DRAM refresh cycle
00 15 usec
01 120 usec (1/8 normal)
10 self
--------p-R64--------------------------------
CMOS 64h - AWARD - POWER MANAGEMENT - IRQ activity events #1
SeeAlso: CMOS 65h"AWARD"
Bitfields for AWARD power management IRQ activity events:
Bit(s) Description (Table C0095)
7 Disable PM Event on IRQ11 Activity (1=disable)
6 Disable PM Event on IRQ10 Activity (1=disable)
5 Disable PM Event on IRQ9 Activity (IRQ2 Redir) (1=disable)
4 Disable PM Event on IRQ8 Activity (RTC Alarm) (1=disable)
3 Disable PM Event on IRQ7 Activity (LPT1) (1=disable)
2 Disable PM Event on IRQ6 Activity (Floppy) (1=disable)
1 Disable PM Event on IRQ5 Activity (LPT2) (1=disable)
0 Disable PM Event on IRQ4 Activity (COM1) (1=disable)
--------p-R65--------------------------------
CMOS 65h - AWARD - POWER MANAGEMENT - IRQ activity events #2
SeeAlso: CMOS 64h"AWARD"
Bitfields for AWARD power management:
Bit(s) Description (Table C0096)
7-4 ??? may be unused. Defaults to all 1's
3 Disable PM Event on IRQ15 Activity (1=disable)
2 Disable PM Event on IRQ14 Activity (Hard Disk) (1=disable)
1 Disable PM Event on IRQ13 Activity (Coprocessor) (1=disable)
0 Disable PM Event on IRQ12 Activity (PS/2 Mouse) (1=disable)
----------R65--------------------------------
CMOS 65h - AMI (PicoPower) - PC PIN STAGGER
Bitfields for AMI (PicoPower) PC pin stagger:
Bit(s) Description (Table C0097)
7-6 PC pin stagger period
00 immediate
01 4 msec
10 16 msec
11 64 msec
--------p-R66--------------------------------
CMOS 66h - AMI 1990 Hyundai super-NB368S notebook - DOZE MODE TIMEOUT
Note: doze mode timeout 00-0F, from table (0,12 -14 sec)
----------R6679------------------------------
CMOS 66h - AWARD - ??? unused ???
Note: Defaults to FFh
----------R6679------------------------------
CMOS 67h - AWARD - TYPE OF FIRST DRIVE ON SECOND IDE PORT
----------R67--------------------------------
CMOS 67h - AMI 1990 Hyundai super-NB368S notebook - SLEEP MODE TIMEOUT
Desc: sleep mode timeout 00-0F, units of 1 second
----------R68--------------------------------
CMOS 68h - AMI 1990 Hyundai super-NB368S notebook - SUSPEND MODE TIMEOUT
Desc: suspend mode timeout 01-0F, units of 5 minutes
----------R686F------------------------------
CMOS 68h-6Fh - AWARD - IDE hard disk params for first drive on second IDE port
----------R69--------------------------------
CMOS 69h - AMI 1990 Hyundai super-NB368S notebook - LCD MODE TIMEOUT
Desc: LCD mode timeout 01-0F, units of 1 minute
----------R6A--------------------------------
CMOS 6Ah - AMI 1990 Hyundai super-NB368S notebook - ???
----------R70--------------------------------
CMOS 70h - AWARD - TYPE OF SECOND DRIVE ON SECOND IDE PORT
----------R7178------------------------------
CMOS 71h-78h - AWARD - IDE hard disk params for second drive on second IDE port
----------R787D------------------------------
CMOS 78h-7Dh - AMI WinBIOS - used by BIOS as scratch RAM
----------R79--------------------------------
CMOS 79h - AWARD - SECONDARY IDE DRIVE TRANSLATION
Bitfields for AWARD Secondary IDE drive translation:
Bit(s) Description (Table C0098)
7-4 ??? Default = 1111
3-2 translation used for secondary master
00 normal, 01 LBA, 10 Large, 11 Autio
1-0 translation used for secondary slave (as for bits 3-2)
----------R7A--------------------------------
CMOS 7Ah - AWARD - EXTENDED CMOS CHECKSUM (high byte)
Note: Award's extended checksum is the arithmetic sum of all the bytes
from 40h (64 decimal) through 79h (121 decimal). [42h-79h for v4.50G]
SeeAlso: CMOS 7Bh"AWARD"
----------R7B--------------------------------
CMOS 7Bh - AWARD - EXTENDED CMOS CHECKSUM (low byte)
Note: Award's extended checksum is the arithmetic sum of all the bytes
from 40h (64 decimal) through 79h (121 decimal). [42h-79h for v4.50G]
SeeAlso: CMOS 7Ah"AWARD"
----------R7D--------------------------------
CMOS 7Dh - AMD-645 Clock - DATE ALARM
Desc: on an AMD-645, this byte specifies the day of the month on which
the alarm will activate
SeeAlso: CMOS 01h,CMOS 03h,CMOS 05h,CMOS 7Eh
----------R7E--------------------------------
CMOS 7Eh - AMD-645 Clock - MONTH ALARM
Desc: on an AMD-645, this byte specifies the month of the year on which
the alarm will activate
SeeAlso: CMOS 01h,CMOS 03h,CMOS 05h,CMOS 7Dh
--------p-R7E7F------------------------------
CMOS 7Eh-7Fh - AMI WinBIOS - used as scratch RAM by power management code
----------R7F--------------------------------
CMOS 7Fh - AMD-645 Clock - CENTURY
SeeAlso: CMOS 32h
---------------------------------------------
--------!---Admin----------------------------
Highest Table Number = C0099
--------!---History--------------------------
Revision History
v1.26 Sep, 1995 reformatted (Ralf)
v1.25 June 1995 Added AMI WinBIOS info from Daniel Miller (Ralf)
v1.24 Jan, 1995 Added Award info from Tim Farley (Ralf)
v1.23 June, 1994 Added some MCA info from _The_Undocumented_PC_
v1.22 Feb, 1994 Added NMI mask note
v1.21 Jan, 1994 Added note for PS/2 checksum found
v1.20 Sept, 1993 PHOENIX data from Wim Osterholt added
additional AMI data from Howie (hjh@gwd.dst.gov.au)
v1.15 June, 1993 AMSTRAD data updated
v1.1 June, 1993 AMSTRAD & PS/2 data added
v1.0 June, 1993 First release: Motorola MC 146818, PC-AT & AMI
"Hi-Flex" information baselined
--------!---CONTACT_INFO---------------------
Internet: ralf@pobox.com (currently forwards to ralf@telerama.lm.com)
FIDO: Ralf Brown 1:129/26.1