Appendix A
Genesis MP
70
◆
SCSI Port
Genesis MP uses a SCSI bus for external SCSI devices. The
external SCSI connector is a 25-pin D-type connector. Refer to the
table for the SCSI Connector pin assignments.
The external SCSI port has automatic termination capability. When
no external SCSI device is connected, the automatic termination
capability is active. When one or more external SCSI devices are
connected, the automatic termination is removed. The last SCSI
device on the bus requires termination.
SCSI Connector Pin Assignments
Int.
Ext.
Signal
Signal
Pin
Pin
Name
Description
2
8
/DB0
Bit 0 of SCSI data bus
4
21
/DB1
Bit 1 of SCSI data bus
6
22
/DB2
Bit 2 of SCSI data bus
8
10
/DB3
Bit 3 of SCSI data bus
10
23
/DB4
Bit 4 of SCSI data bus
12
11
/DB5
Bit 5 of SCSI data bus
14
12
/DB6
Bit 6 of SCSI data bus
16
13
/DB7
Bit 7 of SCSI data bus
18
20
/DBP
Parity bit of SCSI data bus
25
n.c.
Not Connected
26
25
TPWR
+5 V terminator power
32
17
/ATN
Attention
36
6
/BSY
Bus busy
38
5
/ACK
Handshake acknowledge
40
4
/RST
Bus reset
42
2
/MSG
Message phase
43
19
/SEL
Select
46
15
/C/D
Control or data
48
1
/REQ
Handshake request
50
3
/I/O
Input or output
20,22,24,28
7,9,14,16,
GND
Ground
30,34,& all
18and 24
odd pins
except pin 25