esp-idf/components/driver/sdio_slave/README.md

SDIO workflow

This README is a supplement to the comments in the SDIO slave driver. For more details, see sdio_slave.c.

The diagram are described in mermaid format. You can view the diagrams on Github or with any mermaid renders.

Sending direction

sequenceDiagram
    actor task
    participant ISR
    participant HW
    Note right of HW: always: rx_done.raw = 1, rx_eof.ena= 1

    task-->>ISR: Prepare transfers
    task->>HW: rx_done.ena=1
    activate HW

    %% First ISR triggering transfer
    HW->>ISR: trigger
    activate ISR

    ISR->>HW: rx_done.ena=0
    deactivate HW

    loop every finished descriptor
    note over task, HW: skipped, see below
    end

    opt HW idle && new transfer prepared
    ISR->>HW: Load transfer
    end
    deactivate ISR

    activate HW
    HW->>HW: Host doing RX transfer
    deactivate HW

    HW->>HW: rx_eof.raw=1
    activate HW

    %% Second ISR recycling transfer
    HW->>ISR: trigger
    activate ISR

    ISR-->>HW: rx_done.ena=0

    loop every finished descriptor
    ISR->>HW: rx_eof.raw=0
    deactivate HW
    ISR-->>task: inform
    end

    opt HW idle && new transfer prepared
    note over ISR, HW: Load next transfer if there is...
    end

    deactivate ISR