285
Western Digital Hard Disk Drive OEM Specification
11.59
Write Buffer DMA (EBh)
Com m and Block Output Registers
Com m and Block Input Registers
Register
7
6
5
4
3
2
1
0
Register
7
6
5
4
3
2
1
0
Data
-
-
-
-
-
-
-
-
Data
-
-
-
-
-
-
-
-
Feature
-
-
-
-
-
-
-
-
Error
…See Below …
Sector Count
-
-
-
-
-
-
-
-
Sector Count
-
-
-
-
-
-
-
-
Sector Number
-
-
-
-
-
-
-
-
Sector Number
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Device/Head
1
-
1
D
-
-
-
-
Device/Head
-
-
-
-
-
-
-
-
Command
1
1
1
0
1
0
1
1
Status
…See Below …
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC
UNC
0
IDN
0
ABT
T0N
AMN
BSY
RDY
DF
DSC
DRQ
COR
IDX
ERR
0
0
0
0
0
V
0
0
0
V
0
-
-
0
-
V
Table 250 Write Buffer DMA Command (EBh)
The Write Buffer DMA command transfers a sector of data from the host to the sector buffer of the device. The
sectors of data are transferred through the Data Register 16 bits at a time.
The Read Buffer and Write Buffer commands are synchronized such that sequential Write Buffer and Read Buffer
commands access the same 512 byte within the buffer.
