Aaeon SBC-551 Manual page 38

You can attach up to two floppy disks to the SBC-551/552 onboard
controller. You can use any combination of 5¼" (360 KB and 1.2
MB) and/or 3½" (720 KB, 1.44 MB, and 2.88 MB) drives.
A 34-pin daisy-chain drive connector cable is required for a dual-
drive system. On one end of the cable is a 34-pin flat-cable
connector. On the other end are two sets of floppy disk drive
connectors. Each set consists of a 34-pin flat-cable connector
(usually used for 3½" drives) and a printed-circuit board connector
(usually used for 5¼" drives).
Connecting the floppy drive
1. Plug the 34-pin flat-cable connector into CN3. Make sure that
the red wire corresponds to pin one on the connector.
2. Attach the appropriate connector on the other end of the cable
to the floppy drive(s). You can use only one connector in the
set. The set on the end (after the twist in the cable) connects to
the A: drive. The set in the middle connects to the B: drive.
Pin assignments
The following table lists the pin assignments for the CN3 connec-
tor:
Pin
1~33 (odd)
4, 6
10
14
18
22
26
30
34
30 SBC-551/552 User Manual
Signal
GND
Unused
Motor enable A 12
Driver select A
Direction
Write data
Track 0
Read data
Disk change
Pin Signal
2 High density
8 Index
Driver select B
16 Motor enable B
20 Step pulse
24 Write enable
28 Write protect
32 Select head