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4. ATA Drive Register Set Definition and Protocol
The CompactFlash Memory Card can be configured as a high performance I/O device through the following ways:
•
Standard PC-AT disk I/O address spaces 1F0h-1F7h, 3F6h-3F7h (primary); 170h-177h, 376h-377h
(secondary) with IRQ 14 (or other available IRQ).
•
Any system decoded 16-byte I/O block using any available IRQ.
•
Memory space.
The communication to or from the CompactFlash Memory Card is done using the Task File registers, which provide
all the necessary registers for control and status information. The PCMCIA interface connects peripherals to the host
using four register mapping methods. Table 4-1 is a detailed description of these methods.
Config Index
IO or Memory
0
1
2
2
3
3
4.1. I/O Primary and Secondary Address Configurations
-REG
A9-A4
0
1F(17)
0
1F(17)
0
1F(17)
0
1F(17)
0
1F(17)
0
1F(17)
0
1F(17)
0
1F(17)
0
3F(37)
0
3F(37)
®
CompactFlash
Memory Card Product Manual, Rev. 10.0 © 2002 SANDISK CORPORATION
Table 4-1. I/O Configurations
Standard Configurations
Address
Memory
0-F, 400-7FF
I/O
XX0-XXF
I/O
1F0-1F7, 3F6-3F7
I/O
1F0-1F7, 3F6-3F7
I/O
170-177, 376-377
I/O
170-177, 376-377
Table 4-2. Primary and Secondary I/O Decoding
A3
A2
A1
A0
0
0
0
0
0
0
0
0
1
0
0
1
0
1
0
0
1
0
0
1
1
0
1
1
0
1
1
0
1
1
Drive #
0
Memory Mapped
0
I/O Mapped 16 Contiguous Registers
0
Primary I/O Mapped Drive 0
1
Primary I/O Mapped Drive 1
0
Secondary I/O Mapped Drive 0
1
Secondary I/O Mapped Drive 1
-IORD=0
0
Even RD Data
Even WR Data
1
Error Register
Features
0
Sector Count
Sector Count
1
Sector No.
Sector No.
0
Cylinder Low
Cylinder Low
1
Cylinder High
Cylinder High
0
Select Card/Head
Select Card/Head
1
Status
Command
0
Alt Status
Device Control
1
Drive Address
Reserved
Description
-IOWR=0
Note
1, 2
1
4-1
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