FUJITSU MHZ2250BJ - Manual (Page 249)

5.4 Command Protocol
5.4 Command Protocol
The host should confirm that the BSY bit of the Shadow Block 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.
• EXECUTE DEVICE DIAGNOSTIC
• INITIALIZE DEVICE PARAMETERS
Note: Each FIS type is referred to as follows in this section.
FIS (Frame Information Structure) type Abbreviation
Register - Host to Device RegHD
Register - Device to Host RegDH
DMA Active - Device to Host DMA Active
DMA Setup - Device to Host or Host to Device
(Bidirectional) DMA Setup
Set Device Bits - Device to Host SetDB
BIST Active - Bidirectional BIST Active
PIO Setup - Device to Host PIO Setup
Data - Host to Device or Device to Host (Bidirectional) DATA
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