Compaq 4000N - Manual (Page 81)

Technical Reference Guide
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September1997
4-39
Configuration Byte 9Dh, ESS Audio Configuration Byte
Default Value = 12h
Bit Function
7 Reserved for Game Port Enable
6,5 Audio Address
00 = 22xh
01 = 23xh
10 = 24xh
11 = 25xh
4,3 DMA Channel
00 = Disabled
01 = DMA0
10 = DMA1
11 = DMA3
2,1 IRQ Select
00 = IRQ9
01 = IRQ5
10 = IRQ7
11 = IRQ10
0 ESS Audio Chip Enable
0 = Enabled
1 = Disabled
Configuration Byte 9Eh, ECP DMA Configuration Byte
Default Value = 03h
Bit Function
7..4 Reserved
3 SafeStart Control:
0 = Disable
1 = Enable
2..0 ECP DMA Channel
000 = Invalid
100 = Disabled
All other values (001-011, 101-111) refer to channel no.
Configuration Byte 9Fh-AFh, Asset Tag Serial Number
Configuration Bytes B0h-C3h; Custom Hard Drive Information
These bytes contain the number of cylinders, heads, and sectors per track for hard drives C, D, E,
and F respectively. The mapping for each drive is as follows:
Drive 65 (C) Drive 66 (D) Drive 68 (E) Drive 15 (F) Function
B0h B5h BAh BFh No. of Cylinders, Low Byte
B1h B6h BBh C0h No. of Cylinders, High Byte
B2h B7h BCh C1h No. of Heads
B3h B8h BDh C2h Max ECC Bytes
B4h B9h BEh C3h No. of Sectors Per Track