Detailed Description

SDMMC Low Layer HAL module driver.

Author

MCD Application Team

     This file provides firmware functions to manage the following
     functionalities of the SDMMC peripheral:
      + Initialization/de-initialization functions
      + I/O operation functions
      + Peripheral Control functions
      + Peripheral State functions

Attention

This software is licensed under terms that can be found in the LICENSE file in the root directory of this software component. If no LICENSE file comes with this software, it is provided AS-IS.

==============================================================================
                     ##### SDMMC peripheral features #####
==============================================================================
  [..] The SD/SDMMC MMC card host interface (SDMMC) provides an interface between the AHB
       peripheral bus and MultiMedia cards (MMCs), SD memory cards, SDMMC cards and CE-ATA
       devices.

  [..] The SDMMC features include the following:
       (+) Full compliance with MultiMediaCard System Specification Version 4.51. Card support
           for three different databus modes: 1-bit (default), 4-bit and 8-bit.
       (+) Full compatibility with previous versions of MultiMediaCards (backward compatibility).
       (+) Full compliance with SD memory card specifications version 4.1.
           (SDR104 SDMMC_CK speed limited to maximum allowed IO speed, SPI mode and
            UHS-II mode not supported).
       (+) Full compliance with SDIO card specification version 4.0. Card support
           for two different databus modes: 1-bit (default) and 4-bit.
           (SDR104 SDMMC_CK speed limited to maximum allowed IO speed, SPI mode and
            UHS-II mode not supported).
       (+) Data transfer up to 208 Mbyte/s for the 8 bit mode. (depending maximum allowed IO speed).
       (+) Data and command output enable signals to control external bidirectional drivers

                         ##### How to use this driver #####
==============================================================================
  [..]
    This driver is a considered as a driver of service for external devices drivers
    that interfaces with the SDMMC peripheral.
    According to the device used (SD card/ MMC card / SDMMC card ...), a set of APIs
    is used in the device's driver to perform SDMMC operations and functionalities.

    This driver is almost transparent for the final user, it is only used to implement other
    functionalities of the external device.

  [..]
    (+) The SDMMC clock is coming from output of PLL1_Q or PLL2_R.
     Before start working with SDMMC peripheral make sure that the PLL is well configured.
        The SDMMC peripheral uses two clock signals:
        (++) PLL1_Q bus clock (default after reset)
        (++) PLL2_R bus clock

    (+) Enable/Disable peripheral clock using RCC peripheral macros related to SDMMC
        peripheral.

    (+) Enable the Power ON State using the SDMMC_PowerState_ON(SDMMCx)
        function and disable it using the function SDMMC_PowerState_OFF(SDMMCx).

    (+) Enable/Disable the peripheral interrupts using the macros __SDMMC_ENABLE_IT(hSDMMC, IT)
        and __SDMMC_DISABLE_IT(hSDMMC, IT) if you need to use interrupt mode.

    (+) When using the DMA mode
        (++) Configure the IDMA mode (Single buffer or double)
        (++) Configure the buffer address
        (++) Configure Data Path State Machine

    (+) To control the CPSM (Command Path State Machine) and send
        commands to the card use the SDMMC_SendCommand(SDMMCx),
        SDMMC_GetCommandResponse() and SDMMC_GetResponse() functions. First, user has
        to fill the command structure (pointer to SDMMC_CmdInitTypeDef) according
        to the selected command to be sent.
        The parameters that should be filled are:
         (++) Command Argument
         (++) Command Index
         (++) Command Response type
         (++) Command Wait
         (++) CPSM Status (Enable or Disable).

        -@@- To check if the command is well received, read the SDMMC_CMDRESP
            register using the SDMMC_GetCommandResponse().
            The SDMMC responses registers (SDMMC_RESP1 to SDMMC_RESP2), use the
            SDMMC_GetResponse() function.

    (+) To control the DPSM (Data Path State Machine) and send/receive
         data to/from the card use the SDMMC_DataConfig(), SDMMC_GetDataCounter(),
        SDMMC_ReadFIFO(), SDMMC_WriteFIFO() and SDMMC_GetFIFOCount() functions.

  *** Read Operations ***
  =======================
  [..]
    (#) First, user has to fill the data structure (pointer to
        SDMMC_DataInitTypeDef) according to the selected data type to be received.
        The parameters that should be filled are:
         (++) Data TimeOut
         (++) Data Length
         (++) Data Block size
         (++) Data Transfer direction: should be from card (To SDMMC)
         (++) Data Transfer mode
         (++) DPSM Status (Enable or Disable)

    (#) Configure the SDMMC resources to receive the data from the card
        according to selected transfer mode (Refer to Step 8, 9 and 10).

    (#) Send the selected Read command (refer to step 11).

    (#) Use the SDMMC flags/interrupts to check the transfer status.

  *** Write Operations ***
  ========================
  [..]
   (#) First, user has to fill the data structure (pointer to
       SDMMC_DataInitTypeDef) according to the selected data type to be received.
       The parameters that should be filled are:
        (++) Data TimeOut
        (++) Data Length
        (++) Data Block size
        (++) Data Transfer direction:  should be to card (To CARD)
        (++) Data Transfer mode
        (++) DPSM Status (Enable or Disable)

   (#) Configure the SDMMC resources to send the data to the card according to
       selected transfer mode.

   (#) Send the selected Write command.

   (#) Use the SDMMC flags/interrupts to check the transfer status.

  *** Command management operations ***
  =====================================
  [..]
   (#) The commands used for Read/Write/Erase operations are managed in
       separate functions.
       Each function allows to send the needed command with the related argument,
       then check the response.
       By the same approach, you could implement a command and check the response.