Read Dma (C8H/C9H); Table 84: Read Dma Command (C8H/C9H) - Hitachi IC25N040ATMR04-0 - Travelstar 40GB Laptop Hard Drive 9.5mm 2.5 Inch Notebook HDD Specifications

13.13 Read DMA (C8h/C9h)

Table 84: Read DMA command (C8h/C9h)

Command Block Output Registers
Register
Data
Feature
Sector Count
LBA Low
LBA Mid
LBA High
Device
Command
Error Register
7 6 5
CRC UNC 0
0 0 0
The Read DMA command reads one or more sectors of data from disk media and then transfers the data from the
device to the host. It transfers the sectors 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 the
DMARQ and are performed by the slave-DMA channel. The device issues only one interrupt per command to indi-
cate that the data transfer has terminated and that status is available.
If an uncorrectable error occurs, the read will be terminated at the failing sector.
Output parameters to the device
Sector Count
LBA Low
LBA High/Mid
H
R
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
1 L 1 D H H H H
1 1 0 0 1 0 0 R
4 3 2 1
IDN 0 ABT T0N AMN
0 0 V 0
This indicates the number of continuous sectors to be transferred. If zero is specified,
256 sectors will be transferred.
This indicates the sector number of the first sector to be transferred. (L = 0).
In LBA mode, this register specifies that LBA address bits 0–7 are to be transferred
(L = 1)
This indicates the cylinder number of the first sector to be transferred. (L = 0).
In LBA mode this register specifies LBA address bits 8–15 (Mid) and 16–23 (High) to be
transferred. (L = 1)
This indicates the head number of the first sector to be transferred. (L = 0).
In LBA mode this register specifies the LBA bits 24–27 to be transferred. (L = 1)
This indicates the retry bit, but this bit is ignored.
Travelstar 80GN Hard Disk Drive Specification
Command Block Input Registers
Register
Data
Error
Sector Count
LBA Low
LBA Mid
LBA High
Device
Status
0 7 6
BSY RDY DF DSC DRQ
0 0 V
124
7 6 5 4 3 2 1 0
- - - - - - - -
see below
V V V V V V V V
V V V V V V V V
V V V V V V V V
V V V V V V V V
- - - - - H H H H
see below
Status Register
5 4 3 2
COR IDX
0 - - 0
1 0
ERR
- V