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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 12-218 and Figure 12-219 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 12-218 Sequential Read Operation (MMCs Only)
Figure 12-219 Sequential Write Operation (MMCs Only)Figure 12-220 and Figure 12-221 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).
Figure 12-220 Multiple Block Read Operation
Figure 12-221 Multiple Block Write Operation With Card Busy Signal