Diskette Drive Programming; Table 5-6. Diskette Drivec - Compaq Deskpro 4000 Technical Reference Manual

Chapter 5 Input/Output Interfaces
5.3.1

DISKETTE DRIVE PROGRAMMING

5.3.1.1 Diskette Drive Interface Configuration
The diskette drive controller must be configured for a specific address and also must be enabled
before it can be used. Address selection and enabling of the diskette drive interface are affected
by firmware through the PnP configuration registers of the 87307 I/O controller.
The PnP configuration registers are accessed through I/O registers 15Ch (index) and 15Dh
(data). The diskette drive I/F is initiated by firmware selecting logical device 3 of the 87307. This
is accomplished by the following sequence:
1. Write 07h to I/O register 15Ch.
2. Write 03h to I/O register 15Dh (this selects the diskette drive I/F).
3. Write 30h to I/O register 15Ch.
4. Write 01h to I/O register 15Dh (this activates the interface).
The diskette drive I/F configuration registers are listed in the following table:
Table 5–6. Diskette Drive Controller Configuration Registers
Diskette Drive Interface Configuration Registers
Index
Address Function
30h Activate
31h I/O Range Check
60h Base Address MSB
61h Base Address LSB
70h Interrupt Select
71h Interrupt Type
74h DMA Channel Select
75h Report DMA Assignment
F0h Configuration Data
F1h Drive ID
5-10 Compaq Deskpro 4000 and 6000 Personal Computers
featuring the Pentium II Processor
Table 5-6.
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
RO
R/W
R/W
First Edition – October 1997
Reset
Value
01h
00h
03h
F0h
06h
03h
02h
04h
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