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Ata register set and protocol, 1 i/o primary and secondary address configurations – SanDisk CompactFlash Extreme III User Manual

Page 45

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CHAPTER 4

ATA Register Set and Protocol

SanDisk CompactFlash Memory cards 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 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.

Table 4-1

Standard I/O Configurations

Config Index

I/O or Memory

Address

Drive

Description

0

Memory

0-F, 400-7FF

0

Memory Mapped

1

I/O

XX0-XXF

0

I/O Mapped 16 Contiguous
Registers

2

I/O

1F0-1F7, 3F6-3F7

0

Primary I/O Mapped Drive 0

2

I/O

1F0-1F7, 3F6-3F7

1

Primary I/O Mapped Drive 1

3

I/O

170-177, 376-377

0

Secondary I/O Mapped Drive 0

3

I/O

170-177, 376-377

1

Secondary I/O Mapped Drive 1

4.1

I/O Primary and Secondary Address Configurations

Table 3-2 contains configurations for primary and secondary I/O decoding.

Table 4-2

Primary and Secondary I/O Decoding

-REG

A9-A4

A3

A2

A1

A0

-IORD=0

-IOWR=0

0

1F(17)

0

0

0

0

Even RD Data

a,b

Even WR Data

a,b

0

1F(17)

0

0

0

1

Error Register

a

Features

a

0

1F(17)

0

0

1

0

Sector Count

Sector Count

0

1F(17)

0

0

1

1

Sector No.

Sector No.

0

1F(17)

0

1

0

0

Cylinder Low

Cylinder Low

0

1F(17)

0

1

0

1

Cylinder High

Cylinder High

0

1F(17)

0

1

1

0

Select Card/Head

Select Card/Head

0

1F(17)

0

1

1

1

Status

Command

0

3F(37)

0

1

1

0

Alt Status

Device Control

0

3F(37)

0

1

1

1

Drive Address

Reserved

© 2007 SanDisk Corporation

4-1

Rev. 12.0, 02/07

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