Deskstar T7K250 Hard Disk Drive Specification
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12.58 Write Stream DMA (3Ah)
The Write Stream DMA command allows the host to write data using the DMA data transfer protocol. This com-
mand allows for the host to specify to the device that additional actions need to be performed prior to the comple-
tion of the command if the required bits are set.
If the Write Continuous bit is set to one, the device shall not stop execution of the command due to errors. If the
WC bit is set to one and errors occur in the transfer or writing of the data, the device shall continue to transfer the
amount of data requested and then provide ending status with the BSY bit cleared to zero, the SE bit set to one, the
ERR bit cleared to zero, and the type of error, ICRC, IDNF, or ABRT, reported in the error log. If the WC bit is set
to one and the Command Completion Time Limit expires, the device shall stop execution of the command and pro-
vide ending status with BSY bit cleared to zero, the SE bit set to one, the ERR bit cleared to zero, and report the
fact that the Command Completion Time Limit expired by setting the CCTO bit in the error log to one, In all cases,
the device shall attempt to transfer the amount of data requested within the Command Completion Time Limit
event if some data transferred is in error.
Output parameters to the device
Feature Current The number of continuous sectors to be transferred low order, bits (7:0)
URG (bit 7) URG specifies an urgent transfer request. The Urgent bit specifies that the command
should be completed in the minimum possible time by the device and shall be completed
within the specified Command Completion Time Limit.
WC (bit 6) WC specifies Write Continuous mode enabled. If the Write Continuous bit is set to one,
the device shall not stop execution of the command due to errors.
Command Block Output Registers Command Block Input Registers
Register 7 6 5 4 3 2 1 0 Register 7 6 5 4 3 2 1 0
Data Low - - - - - - - - Data Low - - - - - - - -
Data High - - - - - - - - Data High - - - - - - - -
Feature
Current - - - - - - - -
Error see below
Previous - - - - - - - -
Sector
Count
Current V V V V - V V V
Sector
Count
HOB=0 - - - - - - - -
Previous V V V V V V V V HOB=1 - - - - - - - -
Sector
Number
Current V V V V V V V V
Sector
Number
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
Cylinder
Low
Current V V V V V V V V
Cylinder
Low
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
Cylinder
High
Current V V V V V V V V Cylinder
High
HOB=0 V V V V V V V V
Previous V V V V V V V V HOB=1 V V V V V V V V
Device/Head 1 1 1 D - - - - Device/Head - - - - - - - -
Command 0 0 1 1 1 0 1 0 Status See below ...
Error Register Status Register
7654321 0 76543 21 0
CRC UNC 0 IDN 0 ABT T0N AMN BSY RDY DF DSC DRQ COR IDX ERR
VV0V0V0 V 0VVV- 0- V
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