Technical Reference Guide
Compaq Deskpro Personal Computers
Third Edition - April 2001
5-3
5.2.2 IDE CONNECTOR
This system uses a standard 40-pin connector for the primary IDE device and connects (via a
cable) to the hard drive installed in the right side drive bay. Note that some signals are re-defined
for UATA/33 and UATA/66 modes, which require a special 80-conductor cable (supplied)
designed to reduce cross-talk. Device power is supplied through a separate connector.
Figure 5-1. 40-Pin Primary IDE Connector (on system board).
Table 5–3. 40-Pin Primary IDE Connector Pinout
Table 5-3.
40-Pin Primary IDE Connector Pinout
Pin Signal Description Pin Signal Description 
1 RESET- Reset  21 DRQ  DMA Request 
2 GND Ground  22 GND  Ground 
3  DD7  Data Bit <7>  23  IOW-  I/O Write [1] 
4  DD8  Data Bit <8>  24  GND  Ground 
5  DD6  Data Bit <6>  25  IOR-  I/O Read [2] 
6  DD9  Data Bit <9>  26  GND  Ground 
7  DD5  Data Bit <5>  27  IORDY  I/O Channel Ready [3] 
8  DD10  Data Bit <10>  28  CSEL  Cable Select 
9  DD4  Data Bit <4>  29  DAK-  DMA Acknowledge 
10  DD11  Data Bit <11>  30  GND  Ground 
11  DD3  Data Bit <3>  31  IRQn  Interrupt Request [4] 
12  DD12  Data Bit <12>  32  IO16-  16-bit I/O 
13  DD2  Data Bit <2>  33  DA1  Address 1 
14  DD13  Data Bit <13>  34  DSKPDIAG  Pass Diagnostics 
15  DD1  Data Bit <1>  35  DA0  Address 0 
16  DD14  Data Bit <14>  36  DA2  Address 2 
17  DD0  Data Bit <0>  37  CS0-  Chip Select 
18  DD15  Data Bit <15>  38  CS1-  Chip Select 
19  GND  Ground  39  HDACTIVE-  Drive Active (front panel LED) [5] 
20 --  Key  40 GND  Ground 
NOTES: 
  [1] On UATA/33 and higher modes, re-defined as STOP. 
  [2] On UATA/33 and higher mode reads, re-defined as DMARDY-. 
       On UATA/33 and higher mode writes, re-defined as STROBE. 
  [3] On UATA/33 and higher mode reads, re-defined as STROBE-. 
       On UATA/33 and higher mode writes, re-defined as DMARDY-. 
[4] Primary connector wired to IRQ14, secondary connector wired to IRQ15. 
[5] Pin 39 is used for spindle sync and drive activity (becomes SPSYNC/DACT-)  
      when synchronous drives are connected.