IBM IC35L020 - Deskstar 20 GB Hard Drive - Read DMA (C8 H;C9 H); Figure 90. Read DMA Command (C8 H;C9 H)

15.12 Read DMA (C8h/C9h)
see below
Status
1 1 0 0 1 0 0 R
Command
- - - - H H H H
Device/Head
1 L 1 D H H H H
Device/Head
V V V V V V V V
Cylinder High
V V V V V V V V
Cylinder High
V V V V V V V V
Cylinder Low
V V V V V V V V
Cylinder Low
V V V V V V V V
Sector Number
V V V V V V V V
Sector Number
V V V V V V V V
Sector Count
V V V V V V V V
Sector Count
see below
Error
- - - - - - - -
Feature
- - - - - - - -
Data
- - - - - - - -
Data
7 6 5 4 3 2 1 0
Register
7 6 5 4 3 2 1 0
Register
Command Block Input
Registers
Command Block Output
Registers
V–0–V0V0V0V0V0VV
ERRIDXCORDRQDSCDFRDYBSYAMNT0NABT0IDN0UNCCRC
0123456701234567
Status RegisterError Register
Figure 90. 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.
Output parameters to the device
Sector Count
The number of continuous sectors to be transferred. If zero is specified, then 256
sectors will be transferred.
Sector Number
The sector number of the first sector to be transferred. (L=0)
In LBA mode, this register specifies LBA address bits 0–7 to be transferred.
(L=1)
Cylinder High/Low
The cylinder number of the first sector to be transferred. (L=0)
In LBA mode this register specifies LBA address bits 8–15 (Low) 16–23 (High) to
be transferred. (L=1)
Deskstar 60 GXP Hard disk drive specification
124