MMC Card Reader

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This project aims to develop an MMC Card Reader, interfacing with a 8/16 bits embedded system such as the dsPic33F development board.


The use of MMC in embedded systems enables the systems to possess a removable, upgradeable and external mass storage.

Manufacturers usually formats the cards in FAT12/FAT16/FAT32, and can be read/write in almost all computers. This project aims to integrate a FAT file system in freertos_posix for reading/writing files in MMC by 8/16-bit embedded systems. The API employs POSIX and Standard C-library standard for I/O operations.

While our MMC card reader will use the MMC protocol, we probably won't use actual MMC cards. MultiMedia Card (MMC) is long obsolete and superseded by SD and SDHC. We will most likely use the more commonly available SD cards, which support both the MultiMediaCard protocol and the SD protocol. The MMC protocol is the easiest way to communicate with SD cards. SD cards have relatively high density, rewritability and low cost.


  • Save large files (e.g. html) for application feature expansion
  • Provide storage space for upload and upgrade firmware remotely (e.g. over the Internet)
  • Save fonts, image files for GUI applications


  • File read/write access may be slow


MMC Card Reader Development

  • Describe the development of the project