User Manual

ATA Command Description

5-16 CompactFlash

Features 01H and 81H are used to enable and clear 8 bit data transfer mode. If the 01H feature command is issued,

all data transfers will occur on the low order D7-D0 data bus and the IOIS16 signal will not be asserted for data

A host can choose the transfer mechanism by Set Transfer Mode and specifying a value in the Sector Count register.

The upper 5 bits define the type of transfer and the low order 3 bits encode the mode value.

PIO Default Transfer Mode 00000 00d

PIO Flow Control Transfer Mode x 00001 nnn

Multiword DMA Mode x 00100 nnn

Reserved 01000 nnn

Reserved 10000 nnn

Where “nnn” is a valid mode number in binary, “x” is the mode number in decimal for the associated transfer type,

and “d” is ignored.

Features 55H and BBH are the default features for the CompactFlash Memory Card; thus, the host does not have to

issue this command with these features unless it is necessary for compatibility reasons.

The 9AH Feature is accepted for backward compatibility with the SDP Series but has no impact on the

CompactFlash Memory Card. SanDisk does not recommend the use of this command in new designs.

Features 66H and CCH can be used to enable and disable whether the Power On Reset (POR) Defaults will be set

when a soft reset occurs. The default setting is to revert to the POR defaults when a soft reset occurs. POR defaults

the number of heads and sectors along with 16 bit data transfers and the read/write multiple block count.

5.1.18. Set Multiple Mode—C6H

Table 5-23. Seat Multiple Mode

Bit -> 7 6 5 4 3 2 1 0

Command (7) C6H

C/D/H (6) X Drive X

Cyl High (5) X

Cyl Low (4) X

Sec Num (3) X

Sec Cnt (2) Sector Count

Feature (1) X

This command enables the CompactFlash Card to perform Read and Write Multiple operations and establishes the

block count for these commands. The Sector Count Register is loaded with the number of sectors per block. The

current version of the CompactFlash Card supports only a block size of 1 sector per block. Future versions may

support larger block sizes. Upon receipt of the command, the CompactFlash Card sets BSY to 1 and checks the

Sector Count Register.