Fujitsu MHV2060AS, MHV2080AS Command Protocol, PIO Data transferring commands from device to host

5.4 Command Protocol

5.4 Command Protocol

The host should confirm that the BSY bit of the Status register of the device is 0 prior to issue a command. If BSY bit is 1, the host should wait for issuing a command until BSY bit is cleared to 0.

Commands can be executed only when the DRDY bit of the Status register is 1. However, the following commands can be executed even if DRDY bit is 0.

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EXECUTE DEVICE DIAGNOSTIC

INITIALIZE DEVICE PARAMETERS

5.4.1 PIO Data transferring commands from device to host

The execution of the following commands involves data transfer from the device to the host.

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READ SECTOR (S) (EXT)

SMART READ DATA

SMART READ LOG

DEVICE CONFIGURATION IDENTIFY

READ BUFFER

IDENTIFY DEVICE

READ LOG EXT

The execution of these commands includes the transfer one or more sectors of data from the device to the host. In the READ LONG command, 516 bytes are transferred. Following shows the protocol outline.

a)The host writes any required parameters to the Features, Sector Count, Sector Number, Cylinder, and Device/Head registers.

b)The host writes a command code to the Command register.

c)The device sets the BSY bit of the Status register and prepares for data transfer.

d)When one sector of data is available for transfer to the host, the device sets DRQ bit and clears BSY bit. The drive then asserts INTRQ signal.

e)After detecting the INTRQ signal assertion, the host reads the Status register. The host reads one sector of data via the Data register. In response to the Status register being read, the device negates the INTRQ signal.

C141-E221 5-129