Intel® Stratix® 10 Hard Processor System Technical Reference Manual

ID 683222
Date 11/28/2022
Public

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16.4.2.6. Abort During Internal DMA Transfer

If the host issues an SD/SDIO STOP_TRANSMISSION command (CMD12) to the card while data transfer is in progress, the internal DMA controller closes the present descriptor after completing the data transfer until a Data Transfer Over (DTO) interrupt is asserted. Once a STOP_TRANSMISSION command is issued, the DMA controller performs single burst transfers.
  • For a card write operation, the internal DMA controller keeps writing data to the FIFO buffer after fetching it from the system memory until a DTO interrupt is asserted. This is done to keep the card clock running so that the STOP_TRANSMISSION command is reliably sent to the card.
  • For a card read operation, the internal DMA controller keeps reading data from the FIFO buffer and writes to the system memory until a DTO interrupt is generated. This is required because DTO interrupt is not generated until and unless all the FIFO buffer data is emptied.
Note: For a card write abort, only the current descriptor during which a STOP_TRANSMISSION command is issued is closed by the internal DMA controller. The remaining unread descriptors are not closed by the internal DMA controller.
Note: For a card read abort, the internal DMA controller reads the data out of the FIFO buffer and writes them to the corresponding descriptor data buffers. The remaining unread descriptors are not closed.