1.1.6.1 How the Library Works

The SDMMC driver library is a multi-client, multi-instance buffer queue model based block driver interface.

Abstraction Model

The SDMMC driver provides abstraction to communicate with SD/eMMC card through the HSMCI or SDHC peripheral library interface.

SDMMC Driver Features:

• Driver has a buffer queue which allows the capability of accepting multiple requests

• Driver can either have File System as client or Application or USB as client

• Every transfer request expects data in blocks. Block details (Size and number of blocks) can be retrieved by DRV_SDMMC_GeometryGet()

• Driver provides feature to register call back for transfer complete event, which can used by clients to get notified

• Works in both Bare-Metal and RTOS environment in Asynchronous mode

  • Bare-Metal:

    • A dedicated task routine DRV_SDMMC_Tasks() is called from SYS_Tasks() to process the data from the instance queue

  • RTOS:

    • A dedicated thread is created for task routine DRV_SDMMC_Tasks() to process the data from the instance queue

• APIs return with a valid handle which can be used to check whether transfer request is accepted or not

• A Client specific handler will be called to indicate the status of transfer