Read Dma Queued (C7H); Figure 99. Read Dma Queued Command (C7H) - IBM DTLA-305040 - Deskstar 41.1 GB Hard Drive Specifications

12.13 Read DMA Queued (C7h)

Command Block Output
Registers
Register
Data
Feature
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Command
Error Register
7 6 5
CRC UNC 0
V V 0

Figure 99. Read DMA Queued Command (C7h)

This command executes in a similar manner to a READ DMA command. The device may perform a bus
release or it may execute the data transfer without performing a bus release if the data is ready to trans-
fer.
If the device performs a bus release, the host shall reselect the device using the SERVICE command.
Once the data transfer is begun, the device does not perform a bus release until the entire data transfer
has been completed.
Output parameters to the device
Feature
Sector Count
Sector Number
Cylinder High/Low
H
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
V V V V V V V V
1 L 1 D H H H H
1 1 0 0 0 1 1 1
4 3 2 1
IDN 0 ABT T0N AMN
V 0 V 0
number of sectors to be transferred. A value of 00h indicates that 256 sectors
are to be transferred.
bits 7 - 3 (Tag) contain the Tag for the command being delivered.
starting sector number or LBA address bits 7 - 0.
starting cylinder number or LBA address bits 23 - 8.
starting head number or LBA address bits 27 - 24.
Deskstar 40GV & 75GXP hard disk drive specifications
Command Block Input
Register
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Status
Status Register
0 7 6 5
BSY RDY DF
V 0 V 0
130
Registers
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
4 3 2 1
DSC DRQ COR IDX
V – 0 –
0
ERR
V