Programming Summary - IBM 5-1/4" Diskette Drive Adapter Hardware Reference Manual

Bit
No.
Name Symbol
Description
D7 Fault FT This bit is the status of the fault signal
from the FDD.
D6 Write WP This bit is the status of the
Protected
write-protected signal from the FDD.
D5 Ready RY This bit is the status of the ready signal
from the FDD.
D4 Track 0 TO This bit is the status of the track 0 signal
from the FDD.
D3 Two Side
TS This bit is the status of the two-side
signal from the FDD.
D2 Head Address
HD
This bit is the status of the side-select
signal from the FDD.
D1 Unit Select 1
US 1
This bit is the status of the unit-select-1
signal from the FDD.
DO Unit Select 0 USO This bit is the status of the unit-select-O
signal from the FDD.
Command Status Register 3
Programming Summary
FDC Data Register 1/0 Address Hex 3F5
FDC Main Status Register
1/0 Address Hex 3F4
Digital Output Register
1/0 Address Hex 3F2
Bit 0 Drive 00: DR #A 10: DR #C
1 Select 01: DR #B 11: DR #D
2 Not FDC Reset
3 Enable INT & DMA Requests
4 Drive A Motor Enable
5 Drive B Motor Enable
6 Drive C Motor Enable
7 Drive D Motor Enable
All bits cleared with channel reset.
OPC Registers
Diskette Adapter 17