Technical Reference Guide
361834-002
5-3
Input/Output Interfaces
IDE Bus Master Control Registers
The IDE interface can perform PCI bus master operations using the registers listed in Table 5-2.
These registers occupy 16 bytes of variable I/O space set by software and indicated by PCI
configuration register 20h in the previous table.
NOTE:
Unspecified gaps are reserved, will return indeterminate data, and should not be written to.
IDE (PATA) Connector
These systems provide a standard 40-pin connector for a primary IDE device and in most factory
configurations connects to a optical drive (CD or DVD). Some signals are re-defined for
UATA/33 and higher modes. Device power is supplied through a separate connector.
Figure 5-1. 40-Pin IDE (PATA) Connector.
Table 5-2.
IDE Bus Master Control Registers
I/O
Address
Offset
Size
(Bytes)
Register
Default
Value
00h
1
Bus Master IDE Command (Primary)
00h
02h
1
Bus Master IDE Status (Primary)
00h
04h
4
Bus Master IDE Descriptor Pointer (Pri.)
0000 0000h
08h
1
Bus Master IDE Command (Secondary)
00h
0Ah
2
Bus Master IDE Status (Secondary)
00h
0Ch
4
Bus Master IDE Descriptor Pointer (Sec.)
0000 0000h
Summary of Contents for Compaq dc71 Series
Page 50: ...2 34 361834 002 Technical Reference Guide System Overview ...
Page 58: ...3 8 361834 002 Technical Reference Guide Processor Memory Subsystem ...
Page 126: ...5 40 361834 002 Technical Reference Guide Input Output Interfaces ...
Page 168: ...8 20 361834 002 Technical Reference Guide BIOS ROM ...
Page 188: ...A 20 361834 002 Technical Reference Guide Error Messages and Codes ...
Page 192: ...B 4 361834 002 Technical Reference Guide ASCII Character Set ...
Page 210: ...C 18 361834 002 Technical Reference Guide Keyboard ...