HP Compaq dc7600 MT Technical Reference Manual page 89

Diskette Drive Interface Control
The BIOS function INT 13 provides basic control of the diskette drive interface. The diskette
drive interface can be controlled by software through the SCH5307's I/O-mapped registers listed
in Table 5-8. The diskette drive controller of the SCH5307 operates in the PC/AT mode in these
systems.
Primary Second.
Address Address Register
3F0h
3F1h
3F2h
3F3h
Technical Reference Guide
Diskette Drive Interface Control Registers
370h Status Register A:
<7> Interrupt pending
<6> Reserved (always 1)
<5> STEP pin status (active high)
<4> TRK 0 status (active high)
<3> HDSEL status (0 = side 0, 1 = side 1)
<2> INDEX status (active high)
<1> WR PRTK status (0 = disk is write protected)
<0> Direction (0 = outward, 1 = inward)
371h Status Register B:
<7,6> Reserved (always 1's)
<5> DOR bit 0 status
<4> Write data toggle
<3> Read data toggle
<2> WGATE status (active high)
<1,0> MTR 2, 1 ON- status (active high)
372h Digital Output Register (DOR):
<7,6> Reserved
<5,4> Motor 1, 0 enable (active high)
<3> DMA enable (active high)
<2> Reset (active low)
<1,0> Drive select (00 = Drive 1, 01 = Drive 2, 10 = Reserved, 11 =
Tape drive)
373h Tape Drive Register (available for compatibility)
Table 5-8.
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Input/Output Interfaces
R/W
R
R
R/W
R/W
5-9