Intel® Stratix® 10 Hard Processor System Technical Reference Manual

ID 683222
Date 11/28/2022
Public

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16.4.3.2.2.1. Stream Data Read

A stream‑read data transfer occurs if the transfer_mode bit in the cmd register is set to 1, at which time the data path receives data from the card and writes it to the FIFO buffer. If the FIFO buffer becomes full, the card clock stops and restarts once the FIFO buffer is no longer full.

An open‑ended stream‑read data transfer occurs if the bytcnt register is set to 0. During this type of data transfer, the data path continuously receives data in a stream until the host software issues an SD/SDIO STOP command. A stream data transfer terminates two clock cycles after the end bit of the STOP command.

If the bytcnt register contains a nonzero value and the send_auto_stop bit in the cmd register is set to 1, a STOP command is internally generated and loaded into the command path, where the end bit of the STOP command occurs after the last byte of the stream data transfer is received. This data transfer can terminate if the host issues an SD/SDIO STOP or STOP_TRANSMISSION (CMD12) command before all the data bytes are received from the card.