IBM IC35L040AVVN07-0 - 40GB IDE Deskstar 120GXP 7200RPM UATA-100..., Specifications

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8.13 Status Register
ERR IDX CORR DRQ
DSC/
SERV
DF DRDY BSY
0 1 2 3 4 5 6 7
Status Register
Figure 74. Status Register
This register contains the device status. The contents of this register are updated whenever an error
occurs and at the completion of each command.
If the host reads this register when an interrupt is pending, it is considered to be the interrupt acknow-
ledge. Any pending interrupt is cleared whenever this register is read.
If BSY=1, no other bits in the register are valid.
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 zero during power on until the device is ready to accept a command. If
the device detects an error while processing a command, RDY is set to zero until the
Status Register is read by the host, at which time RDY is set back to one.
DF Device Fault. DF = 1 indicates that the device has detected a write fault condition. DF is
set to zero 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 zero 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.
SERV (SRV) Service. SRV is set to one when the device is ready to transfer data after it releases the
bus for execution of a DMA Queued command.
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 zero.
IDX Index. IDX=1 once per revolution. Because IDX=1 only for a very short time during each
revolution, the host may not see it set to one even if the host is continuously reading the
Status Register. 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.
Deskstar 120GXP hard disk drive specifications
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