Table of Contents

X68000 Hard Disk

External HD connector

All X68000s (even the SASI-based models) seem to have standard pinouts for the external hard disk connector:

* Original model, Ace, Expert, Pro: Centronics 50-pin with /ATN, PARITY and Termination Power unconnected.

* Super, XVI: Standard Centronics 50-pin.

* Compact XVI, X68030, X68030 Compact: High-Density Centronics 50-pin.

Internal HD connector

All X68000 machines have a custom internal hard disk connector.

The pinout for the SASI-based machines is as follows:

PinDescriptionPinDescription
1 DB0 11 GND
2 DB1 12 Unknown(Possibly for the HD access LED)
3 GND 13 /BSY
4 DB2 14 /ACK
5 DB3 15 /RST
6 DB4 16 /MSG
7 GND 17 /SEL
8 DB5 18 /C/D
9 DB6 19 REQ
10 DB7 20 /I/O

The pinout for SCSI-based machines(Taken from http://homepage1.nifty.com/ht_deko/x68ktune.html):

PinDescriptionPinDescription
1 DB0 14 /ATN
2 DB1 15 GND
3 GND 16 HD Access LED
4 DB2 17 /BSY
5 DB3 18 /ACK
6 DB4 19 GND
7 GND 20 /RST
8 DB5 21 /MSG
9 DB6 22 /SEL
10 DB7 23 GND
11 GND 24 /C/D
12 PARITY 25 /REQ
13 +5V(Termination power) 26 /I/O

The HDD access LED is nonstandard and mapped to pin 34 of the 50-pin internal SCSI connector. Pulling it low turns on the HDD LED. Most standard SCSI HDDs connect this pin to ground, resulting in the HDD LED staying permanently on.