With an STM32 board with SD card slot availability, this library enables reading and writing on SD card using SD card slot of a STM32 board (NUCLEO, DISCOVERY, ...). This library is for SD card slots connected to the SDIO-/SDMMC-hardware of the processor. For slots connected to SPI-hardware use the standard Arduino SD library.

This library follow Arduino API.

For more information about it, please visit: http://www.arduino.cc/en/Reference/SD

This library is based on FatFs, a generic FAT file system module for small embedded systems.
http://elm-chan.org/fsw/ff

The FatFs has been ported as Arduino library here. The STM32SD library depends on it.

The FatFs has several user defined options, which is specified from within the ffconf.h file.

This library provides a default user defined options file named ffconf_default.h.

User can provide his own defined options by adding his configuration in a file named ffconf_custom.h at sketch level or in variant folder.

Some default definitions can be overridden using:

• board variant.h

• build_opt.h: see Customize build options

• hal_conf_extra.h: see HAL configuration

• SD_INSTANCE: some STM32 can have 2 SD peripherals SDMMC1 and SDMMC2, note that this library can managed only one peripheral

  • SDMMC1 (default)
  • SDMMC2

• SD_HW_FLOW_CTRL: specifies whether the SDMMC hardware flow control is enabled or disabled

  • SD_HW_FLOW_CTRL_ENABLE
  • SD_HW_FLOW_CTRL_DISABLE (default)

• SD_BUS_WIDE: specifies the SDMMC bus width

  • SD_BUS_WIDE_1B
  • SD_BUS_WIDE_4B (default)
  • SD_BUS_WIDE_8B

• SD_TRANSCEIVER_MODE: specifies whether external Transceiver is enabled or disabled. Available only on some STM32

  • SDMMC_TRANSCEIVER_ENABLE
  • SDMMC_TRANSCEIVER_DISABLE (default)

• SD_TRANSCEIVER_EN pin number to enable the level shifter

• SD_TRANSCEIVER_SEL pin number for voltage selection

• SD_DETECT_PIN pin number

• SD_DATATIMEOUT constant for Read/Write block