Specifications

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Floppy Interface Connector
Table 2-16 shows the pinout and signal definitions of the board's floppy disk interface connector,
J8. J8 is identical in pinout with the floppy connector of standard AT and PC floppy controller
boards. Note that, as in a standard PC or AT, both floppy drives are jumpered to the same drive
select -- as the "second" drive. The drives are uniquely selected as a result of a swapping of a
group of seven wires (conductors 10-16) that must occur in the cable between the two drives. The
seven-wire swap goes between the computer board and drive "A"; the wires to drive "B" are
unswapped (or swapped a second time).
Table 2-16. Floppy Disk Interface Connector (J8)
PIN SIGNAL NAME FUNCTION IN/OUT
2 -RPM/-RWC Speed/Precomp out
4 --- (Not used) ---
6 --- (Not used) ---
8 -IDX Index Pulse in
10 -MO1 Motor On 1 out
12 -DS2 Drive Select 2 out
14 -DS2 Drive Select 1 out
16 -MO2 Motor On 2 out
18 -DIRC Direction Select out
20 -STEP Step out
22 -WD Write Delete out
24 -WE Write Enable out
26 -TRK0 Track 0 in
28 -WP Write Protect in
30 -RDD Read Data in
32 -HS Head Select out
34 -DCHG Disk Change in
1-33 (all odd) Signal Grounds ---