SPRUJB6B November 2024 – May 2025 AM2612
There are two types of data transfer:
There are specific commands for each type of operation (sequential or block-oriented). See the Multimedia Card System Specification, the SD Memory Card Specifications, and the SDIO Card Specification.
Stream commands are supported only by MMC cards.
Figure 13-178 and Figure 13-179 show how sequential operations are defined. Sequential operation is only for 1-bit transfer and initiates a continuous data stream. The transfer terminates when a stop command follows on the mmc_cmd line.
Figure 13-178 Sequential Read Operation (MMC Cards Only)
Figure 13-179 Sequential Write Operation (MMC Cards Only)Figure 13-180 and Figure 13-181 show how multiple block-oriented operations are defined. A multiple block-oriented operation sends a data block plus CRC bits. The transfer terminates when a stop command follows on the mmc_cmd line. These operations are available for all kinds of cards.
Figure 13-180 Multiple Block Read Operation (MMC Cards Only)
Figure 13-181 Multiple Block Write Operation (MMC Cards Only)