DIGITAL-LOGIC AG
PCCP5 Manual V2.3
59
BIOS Data Area Definitions
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Location
Description
3Fh
Diskette Drive Motor Status
bit 7
= Current operation
0
=
Write or Format
1
=
Read or Verify
bit 6
= Reserved
bits 5-4 = Drive Select
00
=
Drive A
01
=
Drive B
bits 3-2 = Reserved
0
=
Disable
1
=
Enabled
bit 1
= Drive B Motor Status
0
=
Off
1
=
On
bit 1
= Drive A Motor Status
0
=
Off
1
=
On
40h
Diskette Drive Motor Timeout
Disk drive motor is powered off when the value via the INT 08h
timer interrupt reaches 0.
41h
Diskette Drive Status
bit 7
= Drive Ready
0
=
Ready
1
=
Not ready
bit 6
= Seek Error
0
=
No error
1=
Error occurred
bit 5
= Controller operation
0
=
Working
1
=
Failed
bits 4-0 = Error Codes
00h
=
No error
01h
=
Invalid function requested
02h
=
Address mark not located
03h
=
Write protect error
04h
=
Sector not found
06h
=
Diskette change line active (door
opened)
08h
=
DMA overrun error
09h
=
Data boundary error
0Ch
=
Unknown media type
10h
=
ECC or CRC error
20h
=
Controller failure
40h
=
Seek operation failure
80h
=
Timeout
42h - 48h
Diskette Controller Status Bytes
49h
Video Mode Setting
4Ah - 4Bh
Number of Columns on screen
4Ch - 4Dh
Size of Current Page, in bytes
4Eh - 4Fh
Address of Current Page
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