I think that
the first 34 pins are the same. I only have a few of those
drives, and they are many archeological layers deep. The pinout of the
ones that IBM used on the PS/2s (with the 6 extra pins for power) might be
in the AT "Options and Adapters" Tech Ref
Knowing IBM, I wouldn't be surprised. I think my 2.88 drive is buried in
I don;t think it's in the AT TechRef (at least it's not in mine, and I
have some of the suplements), but there is pinout in the 'Personal
System/2 Hardware Interface Technical Reference'. This is nowhere near as
good a manual as the older TechRefs (no scheamtics, no BIOS sources), but
a friend of mine was goign to throw it out, so I grabbed it :-). Anyway,
here's the drive pinout :
1: 2nd Drive installed/ 2: High Denisity Select/
3: Reserved 4: Reserved
5: Ground 6: Reserved
7: Signal Ground 8: Index/
9: Signal Ground 10: Reserved
11: Signal Ground 12: Drive Select/
13: Ground 14: Reserved
15: Signal Ground 16: Motor Enable/
17: Singal Ground 18: Direction In/
19: Signal Ground 20: Step'
21: Signal Ground 22: Write Data/
23: Signal Ground 24: Write Enable/
25: Signal Ground 26: Track 0/
27: Signal Ground 28: Write Protect/
29: Signal Ground 30: Read Data/
31: Signal Ground 32: Head 1 Select/
33: Signal Ground 34: DIskette Change/
35: Ground 36: Ground
37: Ground 38: +5V DC
39: Ground 40: +12V DC
Note that IBM have re-named some signals, but that the frist 34 really
are an SA400 interface :-). I have no idea what the difference between
'ground' and 'signal ground' is, my guess is they're tied together. I
am
also a little unhappy about only having one pin for each of the supply
rails (the Sony, etc, 3.5" drives with power and data on the same 34 pin
connector use several of the odd-numbered pins for each of the 2 supplies)
Anywhy, there you are...
-tony
