SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
There are two types of data transfer:
There are specific commands for each type of operation (sequential or block-oriented).
For information about commands and programming sequences supported by the MMC, SD, and SDIO devices, see the Multi-Media Card System Specification, SD Memory Card Specifications, and SDIO Card Specification (Part E1).
Figure 12-2196 and Figure 12-2197 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 CMD line.
Stream commands are supported only by MMCs.
Figure 12-2198 and Figure 12-2199 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 CMD line. These operations are available for all kinds of devices (MMC, SD, SDIO).