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19 write dma (cah/cbh) – Toshiba MK6017MAP User Manual

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10.8.19 Write DMA (CAh/CBh)

COMMAND CODE

1 1 0 0 1 0 1 X

REGISTER

REGISTER SETTING

NORMAL COMPLETION

DR

drive no.

no change

CY

starting cylinder

last possible

HD

starting head

last possible

SN

starting sector

last possible

SC

no. of sector to write

00H

FT

no

change

LBA

staring address

last address

This command is basically identical to Sector command except following differences.

Host initialize slave-DMA channel before issuing command.
- Data transfer is initiated by DMARQ and handled by slave-DMA channel in the host.
- Drive issue only one interrupt at the completion of each command to show the status is valid after data
transfer.

During DMA transfer phase, either BSY or DRQ is set to 1.
When a command is completed, CY, HD, SN register (LBA register) shows the sector transferred the latest.
If the drive detects unrecoverable error, the drive terminates the command and CY, HD, SN register (LBA register)
shows the sector where error has occurred.