Seagate ST1000VX000 SV35 Series PATA Product Manual - Page 52
Write Stream DMA 3Ah, FEATURES REGISTER FIELD DESCRIPTIONS, WC Write Continuous
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4.1.5.3 Write Stream DMA (3Ah) Protocol: DMA Out The Write Stream DMA command allows the host to write data using the DMA data transfer protocol. This command allows for the host to specify to the device that additional actions need to be performed prior to the completion of the command if the required bits are set. If the Write Continuous bit is set to 1, the device shall attempt to not stop execution of the command due to errors. If the WC bit is set to 1 and errors occur in the transfer or writing of the data, the device shall attempt to 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 1, the ERR bit cleared to 0. If the WC bit is set to 1 and the Command Completion Time Limit expires, the device shall stop execution of the command and provide ending status with the BSY bit cleared to 0, the SE bit clear, the ERR bit set, and report the fact that the Command Completion Time Limit expired by setting the CCTO bit in the error register. In all cases, the drive shall attempt to transfer the amount of data requested within the Command Completion Time Limit even if some data transferred is in error. Additionally, if the F bit is set for a Write Stream command, the drive shall conclude processing for the command (including flushing it to the media) before posting status. Register Features 7 6 Current Ignored WC 5 4 3 F Ignored r 2 1 0 Ignored Sector Count Previous Current Command Completion Time Limit (7:0) Sector count Previous LBA Low, Mid, High Current LBA Previous Device obs LBA obs DEV Reserved Command 3Ah Note: The value indicated as Current is the value most recently written to the register. The value indicated as Previous is the value that was in the register before the most recent write to the register. FEATURES REGISTER FIELD DESCRIPTIONS WC (Write Continuous) This bit indicates if Write Continuous mode is enabled. 1 The device shall attempt to not stop execution of the command due to errors. If the WC bit is set to 1 and errors occur in the transfer or writing of data, the device shall attempt to continue to transfer the amount of data requested, and then provide ending status with the BSY bit cleared to 0, the SE bit set to 1, and the ERR bit cleared to 0. If the WC bit is set to 1 and the Command COmpletion Time Limit expires, te device shall stop execution of the command and provide ending status with the BSY bit cleared to 0, the SE bit clear, the ERR bit set, and report the fact that the Command Completion Time Limit expired by setting the CCTO bit in the error register to 1. In all cases, the device shall attempt to transfer the amount of data requested within the Command Completion Time Limit even if some data transferred is in error. 46 SV35 Series Product Manual, Rev. B