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Amiga Technical References

2.5" SCSI Connector

This is an excerpt from IBM's technical section.
http://www.storage.ibm.com/techsup/hddtech/dhas/dhaseis.htm

 

     Pin  Signal name   Pin  Signal name
     _______________________________________
     01        +5V         02        +5V
     _______________________________________
     03        RET         04        RET
     _______________________________________
     05        GND         06        DB0
     _______________________________________
     07        GND         08        DB1
     _______________________________________
     09        GND         10        DB2
     _______________________________________
     11        GND         12        DB3
     _______________________________________
     13        GND         14        DB4
     _______________________________________
     15        GND         16        DB5
     _______________________________________
     17        KEY         18        DB6
     _______________________________________
     19        GND         20        DB7
     _______________________________________
     21        GND         22       PARITY
     _______________________________________
     23        GND         24      TERM PWR
     _______________________________________
     25       -ATTN        26       -BSY
     _______________________________________
     27        GND         28       -ACK
     _______________________________________
     29       -RST         30       -MSG
     _______________________________________
     31        GND         32       -SEL
     _______________________________________
     33       -I/O         34       -C/D
     _______________________________________
     35        GND         36       -REQ
     _______________________________________
     37        RET         38        RET
     _______________________________________
     39        +5V         40        +5V
     _______________________________________


The J2 pin assignments: 
     _______________________________________
     Pin  Signal name   Pin  Signal name
     _______________________________________
      1    (Unused)        2    -No Spin Up
     _______________________________________
      3     -INDEX         4     (Unused)
     _______________________________________
      5      -ID1          6       -ID2
     _______________________________________
      7      -ID4          8       -LED
     _______________________________________

Note: If pin 2 is grounded the drive will not spin up at power on. The drive must be started with a start stop unit command.

Signal line descriptions
BSY BUSY indicates that the bus is in use
SEL SELECT is used by an Initiator to select a Target or by a Target to re-select an Initiator
C/D CONTROL DATA indicates whether control (1) or data (0) information is on the bus
I/O INPUT/OUTPUT indicates whether the data on the bus is an input (1) to the Initiator or an output (0) to the Target. This line is also used to differentiate between SELECTION phase (0) and RE-SELECTION phase (1)
MSG MESSAGE is driven by Target and indicates a message phase
REQ REQUEST is driven by Target and indicates a request for a REQ/ACK data transfer handshake
ACK ACKNOWLEDGE is driven by the Initiator and indicates an acknowledgement of a REQ/ACK data transfer handshake
ATN ATTENTION is driven by an Initiator to inform a Target that the Initiator has a message ready
RST RSET clears all SCSI devices from the bus and resets them Note: The target will not drive this line
DB(n) 8 data bits are used to transfer data over the bus. DB(7) is the most significant
DB(P) PARITY bit associated with DB(7-0). Data parity is odd
ID(n) These signal pins are used to set the drive address
INDEX The signal is just for reference, and the function is not specified
LED The signal is just for reference, and the function is not specified


Copyright 2000 Amiga Auckland Inc. All rights reserved.
Revised: June 16, 2005.