Fujitsu MHV2060AS, MHV2080AS, MHV2040AS manual Interface

Interface

-Bit 7: Busy (BSY) bit. This bit is set whenever the Command register is accessed. Then this bit is cleared when the command is completed. However, even if a command is being executed, this bit is 0 while data transfer is being requested (DRQ bit = 1). When BSY bit is 1, the host system should not write the command block registers. If the host system reads any command block register when BSY bit is 1, the contents of the Status register are posted. This bit is set by the device under following conditions:

(a)Within 400 ns after RESET- is negated or SRST is set in the Device Control register, the BSY bit is set. The BSY bit is cleared, when the reset process is completed.

The BSY bit is set for no longer than 15 seconds after the IDD accepts reset.

(b)Within 400 ns from the host system starts writing to the Command register.

(c)Within 5 ∝s following transfer of 512 bytes data during execution of the READ SECTOR(S), WRITE SECTOR(S), or WRITE BUFFER command.

-Bit 6: Device Ready (DRDY) bit. This bit indicates that the device is capable to respond to a command.

The IDD checks its status when it receives a command. If an error is detected (not ready state), the IDD clears this bit to 0. This is cleared to 0 at power-on and it is cleared until the rotational speed of the spindle motor reaches the steady speed.

-Bit 5: The Device Write Fault (DF) bit. This bit indicates that a device fault (write fault) condition has been detected.

If a write fault is detected during command execution, this bit is latched and retained until the device accepts the next command or reset.

-Bit 4: Device Seek Complete (DSC) bit. This bit indicates that the device heads are positioned over a track.

In the IDD, this bit is always set to 1 after the spin-up control is completed.

-Bit 3: Data Request (DRQ) bit. This bit indicates that the device is ready to transfer data of word unit or byte unit between the host system and the device.

-Bit 2: Always 0.

-Bit 1: Always 0.

-Bit 0: Error (ERR) bit. This bit indicates that an error was detected while the previous command was being executed. The Error register indicates the additional information of the cause for the error.

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