Datasheet
13.1 Data In Commands
The Data In Commands include the following:
y Identify Device
y Read Buffer
y Read Long
y Read Multiple
y Read Sectors
y SMART Read Attribute Values
y SMART Read Attribute Thresholds
Execution includes the transfer of one or more 512 byte (>512 bytes on Read Long) sectors of data from
the device to the host.
The following is a description of the execution process:
1. The host writes any required parameters to the Features, Sector Count, Sector Number, Cylinder,
and Device/Head Registers.
2. The host writes the command code to the Command Register.
3. For each sector (or block) of data to be transferred:
The device sets BSY=1 and prepares for data transfer.
When a sector (or block) of data is available for transfer to the host, the device sets BSY=0, sets
DRQ=1, and interrupts the host.
In response to the interrupt, the host reads the Status Register.
The device clears the interrupt in response to the Status Register being read.
The host reads one sector (or block) of data via the Data Register.
The device sets DRQ=0 after the sector (or block) has been transferred to the host.
4. For the Read Long command:
The device sets BSY=1 and prepares for data transfer.
When the sector of data is available for transfer to the host, the device sets BSY=0, sets
DRQ=1, and interrupts the host.
In response to the interrupt, the host reads the Status Register.
The device clears the interrupt in response to the Status Register being read.
The host reads the sector of data including ECC bytes via the Data Register.
The device sets DRQ=0 after the sector has been transferred to the host.
The Read Multiple command transfers one block of data for each interrupt. The other commands transfer
one sector of data for each interrupt.
Note that the status data for a sector of data is available in the Status Register before the sector is trans-
ferred to the host.
If the device detects an invalid parameter, then it will abort the command by setting BSY=0, ERR=1,
ABT=1, and interrupting the host.
If an error occurs, the device will set BSY=0, ERR=1, and DRQ=1. The device will then store the error
status in the Error Register, and interrupt the host. The registers will contain the location of the sector in
Hard disk drive specification for DSCM-11000/-10512/-10340
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