Fujitsu MPF3XXXAH manual Write Buffer XE8

At command completion (I/O registers contents to be read)

1F7H(ST)				Status information
1F6H(DH)	×	×	×		DV	xx
1F5H(CH)					xx
1F4H(CL)					xx
1F3H(SN)					xx
1F2H(SC)					xx
1F1H(ER)				Error information

(21)WRITE BUFFER (X'E8')

The host system can overwrite the contents of the sector 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 sector buffer, then generates an interrupt.

At command issuance (I/O registers setting contents)

1F7H(CM)	1	1	1	0	1	0	0	0
1F6H(DH)	×	×	×	DV			xx
1F5H(CH)					xx
1F4H(CL)					xx
1F3H(SN)					xx
1F2H(SC)					xx
1F1H(FR)					xx

At command completion (I/O registers contents to be read)

1F7H(ST)				Status information
1F6H(DH)	×	×	×		DV	xx
1F5H(CH)					xx
1F4H(CL)					xx
1F3H(SN)					xx
1F2H(SC)					xx
1F1H(ER)				Error information

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