Fujitsu MHT2080AH - 80GB 5400 RPM PATA Hard Drive Product Manual page 130

Interface
(22) WRITE BUFFER (X'E8')
The host system can overwrite the contents of the data buffer of the device with a
desired data pattern by issuing this command. Upon receipt of this command, the
device sets the BSY bit of the Status register. Then the device sets the DRQ bit of
Status register and clears the BSY bit when the device is ready to receive the data.
After that, 512 bytes of data is transferred from the host and the device writes the
data to the buffer, then generates an interrupt.
At command issuance (I/O registers setting contents)
1F7 (CM)
H
1F6 (DH)
H
1F5 (CH)
H
1F4 (CL)
H
1F3 (SN)
H
1F2 (SC)
H
1F1 (FR)
H
At command completion (I/O registers contents to be read)
1F7 (ST)
H
1F6 (DH)
H
1F5 (CH)
H
1F4 (CL)
H
1F3 (SN)
H
1F2 (SC)
H
1F1 (ER)
H
5-60
1 1 1 1
x x x DV
xx
xx
xx
xx
xx
Status information
x x x DV
xx
xx
xx
xx
Error information
1 0 0 0
xx
xx
C141-E195-02EN