Hitachi HCS721050CLA382, HCS721032CLA382, A7K2000 Read DMAC8h/C9h, Read DMA Command C8h/C9h

11.15Read DMA(C8h/C9h)

Command Block Output Registers

Register			7	6	5	4	3	2	1		0
Data			-	-	-	-	-	-	-		-
Feature			-	-	-	-	-	-	-		-
Sector Count			V	V	V	V	V	V	V		V
Sector Number			V	V	V	V	V	V	V		V
Cylinder Low			V	V	V	V	V	V	V		V
Cylinder High			V	V	V	V	V	V	V		V
Device/Head			1	L	1	D	H	H	H		H
Command			1	1	0	0	1	0	0		R
			Error Register
7	6	5		4	3		2	1			0
CRC	UNC	0		IDN	0		ABT	T0N		AMN
V	V	0		V	0		V	0			0

Command Block Input Registers

Register

7

6

5

4

3

2

1

0

Data

-

-

-

-

-

-

-

-

Error

...See Below...

Sector Count

V

V

V

V

V

V

V

V

Sector Number

V

V

V

V

V

V

V

V

Cylinder Low

V

V

V

V

V

V

V

V

Cylinder High

V

V

V

V

V

V

V

V

Device/Head

-

-

-

-

H

H

H

H

Status

...See Below...

Status Register

7

6

5

4

3

2

1

0

BSY

RDY

DF

DSC

DRQ

COR

IDX

ERR

0

V

0

V

-

0

-

V

Table 96 Read DMA Command (C8h/C9h)

The Read DMA command reads one or more sectors of data from disk media, then transfers the data from the device to the host.

The sectors are transferred through the Data Register 16 bits at a time.

The host initializes a slave-DMA channel prior to issuing the command. The data transfers are qualified by DMARQ and are performed by the slave-DMA channel. The device issues only one interrupt per command to indicate that data transfer has terminated and status is available.

If an uncorrectable error occurs, the read will be terminated at the failing sector.

Hitachi hard disk drive specifications

138