Product manual

Barracuda 2LP Product Manual, Rev. D 77
Table 14. Single-ended cable pin assignments
(non-shielded connector) for ST31250N
and ST32550N drives
Signal Pin number Signal Pin number
−DB (0) 2 GROUND 28
−DB (1) 4 GROUND 30
−DB (2) 6 −ATN 32
−DB (3) 8 GROUND 34
−DB (4) 10 −BSY 36
−DB (5) 12 −ACK 38
−DB (6) 14 −RST 40
−DB (7) 16 −MSG 42
−DB (P) 18 −SEL 44
GROUND 20 −C/D 46
GROUND 22 −REQ 48
GROUND 24 −I/O 50
TERMPWR 26
Notes:
1. All odd pins except pin 25 are connected to ground. Pin 25 is left open.
Caution. Do not connect pin 25 to ground at the host end or the drive end
of the cable. If you accidentally plug in the I/O connector upside
down, terminator power on pin 26 will be shorted to ground.
2. The minus sign next to a signal indicates asserted state is the low voltage
of the two levels used for logic signals.