本帖最后由 xmshao 于 2018-5-9 17:11 编辑 指令那么多，不用某部分指令你照样完成任务。 就像写代码，每个人常用的指令并不完全相同，一般也不影响事。 5.2 IO_RW_EXTENDED command (CMD53) In order to read and write multiple I/O registers with a single command, a new command, IO_RW_EXTENDED is defined. This command is included in command class 9 (I/O Commands). This command allows the reading or writing of a large number of I/O registers with a single command. Since this is a data transfer command, it provides the highest possible transfer rate. The response from the SDIO card to CMD53 will be R5 (the same as CMD52). For CMD53, the 8-bit data field will be stuff bits and shall be read as 0x00. 5.2.1 CMD53 Data Transfer Format When executing the IO_RW_EXTENDED (CMD53), the multi-byte or multi-block data transfer is similar to the data transfer for memory. For the multi-byte transfer modes (block mode=0) the following applies: IO_RW_EXTENDED byte read is similar to CMD17 (READ_SINGLE_BLOCK) IO_RW_EXTENDED byte write is similar to CMD24 (WRITE_BLOCK) Note that the byte count for this transfer is set in the command, rather than the fixed block size. Thus, the size of the data payload will be in the range of 1-512 bytes. The block mode is similar to the following memory commands: IO_RW_EXTENDED block read is similar to CMD18 (READ_MULTIPLE_BLOCK) IO_RW_EXTENDED block write is similar to CMD25 (WRITE_MULTIPLE_BLOCK) For the block mode the only difference is that for a fixed block count, the host does not need to stop the transfer, as it will continue until the block count is satisfied. If the block count is set to zero, the operation is identical to the memory mode in that the host must stop the transfer. 关于SD卡的应用,ST或第三方都有参考代码可以参考的。
