Intel® Agilex™ Hard Processor System Technical Reference Manual

ID 683567
Date 11/11/2022
Public

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16.5.9.5.5. The FLUSH CACHE EXT Command

For card devices that buffer/cache written data, the FLUSH CACHE EXT command ensures that buffered data is written to the card media. For cards that do not buffer written data, the FLUSH CACHE EXT command returns a success status. No data transfer (RW_BLK) is expected for this ATA command.

The host issues a RW_REG command for the ATA command, and the status is retrieved with the SD/SDIO CMD39 or RW_REG command. There can be error status for this ATA command, in which case fields other than the status field of the ATA task file are valid.

The host controller uses the following settings while sending the RW_REG command for the STANDBY IMMEDIATE ATA command:

  • cmd register setting: data_expected bit set to 0
  • cmdarg register settings:
    • Bit [31] set to 1
    • Bits [7:2] set to 4
    • All other bits set to 0
  • Task file settings:
    • Command field of the ATA task file set to 0xEA
    • Reserved fields of the task file set to 0
  • bytcnt register and block_size field of the blksiz register: set to 16