IBM HD Controller Pinouts

XT-Bus (8-bit) IDE Connector
IBM XT Bus IDE Connector (Model 25 and 30)
MCA DBA (Direct Bus Attachment) Hard Drive Connector (Model 50 and 70)
ATA Connector (Lacuna 9577, 9533, 9553)


XT-Bus (8-bit) IDE Connector

PinSignalPinSignal
1-RESET2Ground
3Data Bit 74Ground
5Data Bit 66Ground
7Data Bit 58Ground
9Data Bit 410Ground
11Data Bit 312Ground
13Data Bit 214Ground
15Data Bit 116Ground
17Data Bit 018Ground
19Ground20Key (Missing pin)
21AEN22Ground
23-IOW24Ground
25-IOR26Ground
27-DACK 328Ground
29DRQ 330Ground
31IRQ 532Ground
33Address Bit 134Ground
35Address Bit 036Ground
37-CS1FX38Ground
39-Drive Active40Ground


IBM XT-Bus IDE Connector (PS/2 Model 25 and 30)

PinSignalPinSignal
1-RESET2-Disk Installed
3Data Bit 04Ground
5Data Bit 16Ground
7Data Bit 28Ground
9Data Bit 310Ground
11Data Bit 412Ground
13Data Bit 514Ground
15Data Bit 616Ground
17Data Bit 718Ground
19-IOR20Ground
21-IOW22Ground
23-CS1FX24Ground
25Address Bit 026Ground
27Address Bit 128Ground
29Address Bit 230+5 Vdc
31Reserved32+5 Vdc
33-DACK 334Ground
35DRQ 336Ground
37IRQ 538Ground
39I/O CH RDY40+12 Vdc
41Spare42+12 Vdc
43Spare44+12 Vdc


MCA DBA (Direct Bus Attachment) Hard Drive Connector (Model 50 and 70)

For those of you out there that recognize it, yes it is a subset of the standard Micro Channel slot (16-bit version).

PinSignalPinSignal
A1-CD SETUPB1Address Bit 15
A2Address Bit 13B2Address Bit 14
A3GroundB3Ground
A4Address Bit 11B4OSC (14.3 MHz)
A5Address Bit 10B5Ground
A6Address Bit 9B6Address Bit 12
A7+5 VdcB7-CMD
A8Address Bit 8B8-CD SFDBK
A9Address Bit 7B9Ground
A10Address Bit 6B10Data Bit 1
A11GroundB11Data Bit 3
A12Address Bit 5B12Data Bit 4
A13Address Bit 4B13Ground
A14Address Bit 3B14CHRESET
A15+5 VdcB15Data Bit 8
A16Address Bit 2B16Data Bit 9
A17Address Bit 1B17Ground
A18Address Bit 0B18Data Bit 12
A19+12 VdcB19Data Bit 14
A20-ADLB20Data Bit 15
A21-PREEMPTB21Ground
A22-BURSTB22Data Bit 0
A23+5 VdcB23Data Bit 2
A24ARB 0B24Data Bit 5
A25ARB 1B25Ground
A26ARB 2B26Data Bit 6
A27+12 VdcB27Data Bit 7
A28ARB 3B28Data Bit 10
A29+ARB/-GRANTB29Ground
A30-TCB30Data Bit 11
A31+5 VdcB31Data Bit 13
A32-S0B32-SBHE
A33-S1B33Ground
A34+M/-IOB34-CD DS 16
A35GroundB35-IRQ 14
A36CD CHRDYB36Ground

Ed. Tom: Pin A11 was listed as +5 V DC instead of Ground (see Model 70 SSI). I have measured this on my Model 70, and pin A11 indeed is tied to the ground. Scott Mueller's Upgrading and Repairing PCs has this error as well!


ATA Connector (Lacuna, 9533, 9553)

PinSignalPinSignal
1-RESET2Ground
3Data Bit 74Data Bit 8
5Data Bit 66Data Bit 9
7Data Bit 58Data Bit 10
9Data Bit 410Data Bit 11
11Data Bit 312Data Bit 12
13Data Bit 214Data Bit 13
15Data Bit 116Data Bit 14
17Data Bit 018Data Bit 15
19Ground20Key (Missing pin)
21DRQ 322Ground
23-IOW24Ground
25-IOR26Ground
27I/O CH RDY28SPSYNC:CSEL
29-DACK 330Ground
31IRQ1432-IOCS16
33Address Bit 134-PDIAG
35Address Bit 036Address Bit 2
37-CS1FX38-CS3FX
39-DA/SP40Ground
41+5 Vdc (Logic)42+5 Vdc (Motor)
43Ground44-Type (0=ATA)


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