IBM DARA-206000 Hard Drive Specifications - Page 82

Bit Definitions, DRDY RDY, CORR COR

Page 82 highlights

Bit Definitions BSY DRDY (RDY) DF DSC DRQ CORR (COR) IDX ERR Busy. B S Y = 1 whenever the device is accessing the registers. The host should not read or write any registers when BSY=1. If the host reads any register when B S Y = 1 , the contents of the Status Register will be returned. Device Ready. R D Y = 1 indicates that the device is capable of responding to a command. R D Y will be set to 0 during power on until the device is ready to accept a command. Device Fault. D F = 1 indicates that the device has detected a write fault condition. D F is set to 0 after the Status Register is read by the host. Device Seek Complete. D S C = 1 indicates that a seek has completed and the device head is settled over a track. DSC is set to 0 by the device just before a seek begins. When an error occurs, this bit is not changed until the Status Register is read by the host, at which time the bit again indicates the current seek complete status. When the device enters into or is in Standby mode or Sleep mode, this bit is set by device in spite of not spinning up. Data Request. D R Q = 1 indicates that the device is ready to transfer a word or byte of data between the host and the device. The host should not write the Command register when D R Q = 1 . Corrected Data. Always 0. Index. I D X = 1 once per revolution. Since I D X = 1 only for a very short time during each revolution, the host may not see it set to 1 even if the host is reading the Status Register continuously. Therefore the host should not attempt to use IDX for timing purposes. Error. E R R = 1 indicates that an error occurred during execution of the previous command. The Error Register should be read to determine the error type. The device sets E R R = 0 when the next command is received from the host. 72 OEM Specifications of DARA-2xxxxx 2.5 inch H D D Rev 2.1

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Bit Definitions
BSY
Busy.
BSY=1 whenever the device is accessing the registers.
The host should not
read
or
write
any registers when BSY=1.
If the
host reads any register when
BSY=1, the contents of the Status Register will be returned.
DRDY (RDY)
Device Ready.
RDY=1
indicates that the device is capable of responding to a
command.
RDY will be set to 0 during power on until the device is ready to accept
a command.
DF
Device Fault.
D F = 1 indicates that the device has detected a write fault condition.
DF is set to 0 after the Status Register is read by the host.
DSC
Device Seek Complete.
DSC=1 indicates that a seek has completed and the device
head is settled over a track.
DSC is set to 0 by the device just before a seek begins.
When an error occurs, this bit is not changed until the Status Register is read by the
host, at which time the bit again indicates the current seek complete status.
When the device enters into or is in Standby mode or Sleep mode, this bit is set by
device in spite of not spinning up.
DRQ
Data Request.
DRQ=1 indicates that the device is ready to transfer a word or byte
of data between the host and the device.
The host should not write the Command
register when DRQ=1.
CORR (COR)
Corrected Data.
Always 0.
IDX
Index. IDX=1 once per revolution.
Since IDX=1 only for a very short time during
each revolution, the host may not see it set to 1 even if the host is reading the Status
Register continuously.
Therefore the host should not attempt to use IDX for timing
purposes.
ERR
Error.
ERR=1
indicates that an error occurred during execution of the previous
command.
The Error Register should be read to determine the error type.
The
device sets ERR=0 when the next command is received from the host.
72
OEM Specifications of DARA-2xxxxx 2.5 inch HDD Rev 2.1