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2 pio data-in command protocol – FUJITSU MHW2120BS User Manual

Page 246

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Interface

5.4.2 PIO data-in command protocol

Execution of the following commands involves data transfers from the device to
the host system:

IDENTIFY DEVICE

READ SECTOR(S) (EXT)

READ MULTI (EXT)

READ BUFFER

READ LOG EXT

An outline of this protocol is as follows:

1) The device receives a PIO data-in command with the RegHD FIS.

3) When the device is ready to send data, it sets 0 in the BSY bit, 1 in the DRQ

bit, and 1 in the I bit of the Status field of the PIO Setup FIS, then sends this
FIS to the host. At this time, if the requested data is read from the last sector
to be processed, the device sets 0 in both the BSY bit and DRQ bit of the
E_Status field. Otherwise, the device sets 1 in the BSY bit and 0 in the DRQ
bit of the E_Status field.

SMART READ DATA

SMATR READ LOG SECTOR

DEVICE CONFIGRATION IDENTIFY

Data of one or more sectors is transferred from the device to the host.

2) If an error remaining in the device prevents command execution, the device

sends the RegDH FIS with 1 set in the I bit.

4) The device sends the DATA FIS to the host.

5) When all data has been transferred, command execution is completed. If any

data remains to be transferred, this protocol is repeated starting from step 3).
(The maximum data size is 8 KB.)

5-172

C141-E249

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