HP Compaq dc7100 DT Technical Reference Manual page 95

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 LPC47B397's I/O-mapped registers
listed in Table 5-8. The diskette drive controller of the LPC47B397 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.
361834-002
Input/Output Interfaces
R/W
R
R
R/W
R/W
5-9