Accessing the CMOS (Cont.)
Bitfields for Zenith Z-200 boot drive selection:
Bit(s) Description (Table C023)
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
----------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 C024)
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)
See Also: 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 C025)
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
See Also: CMOS 26h"Quadtel"
Bitfields for Quadtel landing zone/write-precompensation:
Bit(s) Description (Table C026)
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 C027)
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
See Also: CMOS 1Eh"Quadtel",#C024
----------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
----------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
See Also: CMOS 20h"Quadtel",#C026
----------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 C028)
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 C029)
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
See Also: #C030
----------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