The AK-SDFS-UART-B board allows you to read/write data from/to an SD card using a serial TTL port (UART). The board supports the FAT file system so the files can be read back from the SD on a PC/MAC.

Using a simple protocol (libraries included) you can read/write 4 files concurrently, in text or binary mode. Using only four wires (TX, RX, VCC and GND) you can read and write from the SD using very small microprocessors, even 8-bit ones. The baudrate can be adjusted from 9600 up to 460800 bps.

We have prepared a library that encapsulates the communication protocol and the source code can be downloaded. There is also an Arduino sketch demonstration available for download.

The AK-SDFS-UART-B is perfect to be used as a data logger, for sensors and debug information. It supports SD and SDHC cards.

We also have a micro SD version of this board.


  • Only four wires to get a working FAT File System
  • Powered from 3.3V external supply
  • All I/O pins are 5V tolerant
  • Operates on 4 files concurrently
  • RTC supported (time and date command has to be given at every power up)
  • Supports all file commands as Open, Create, Exist, Close, Write, Flush, Read, Size
  • Supports long file names
  • Supports directory tree listing
  • Commands to create and delete directories
  • Supports binary files
  • Uses a single and secure UART protocol. Source code examples are provided
  • Breadboard-ready
  • Supports firmware upgrade



Additional information

Weight 0.070 kg
Dimensions 20 × 22 × 20 mm


4 years 1 month ago

Are the tx-rx pins 5V tolerant? Or you have to use a voltage level shifter for interfacing with microcontrollers?

4 years 1 month ago

Hi. Sorry for the late reply. All the pins except for RESET are 5V tolerant.

5 years 9 months ago

What is the default baud rate, parity, stop bits communication settings to communicate with the AK-SDFS-UART-B – SD File System Through UART

5 years 9 months ago

Hi. The default settings are 9600, 8-N-1


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AK-SDFS-UART-B - SD File System Through UART

The AK-SDFS-UART-B allows you to write and read files from a standard SD with FAT file system using an UART.


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