The AK-MCP2221 is a breakout board for the Microchip MCP2221 IC that allows you to convert USB to serial UART, I2C/SMBus and also drive GPIOs, like inputs, outputs, DAC, ADC and more.

The board comes with everything you need to start using the MCP2221 in your projects. The USB mini connector is both used for communicating with the board and to supply power to it.

On the board there is a switch to control the TTL level of the signals (3.3V or 5V). If you plan to use this board as an USB to I2C converter, there are two convenient 4K7 Ohm pull-up resistors for the I2C bus that you can enable by joining a couple of solder jumpers.

The board has a row of 1″ (2.54mm) spaced pins with every signal available: SDA and SDL for I2C, RX and TX for the UART, four GPIO pins, reset, VCC and ground.

The MCP2221 works on Windows, Linux and OSX. On the Microchip website you can find all the software needed to start using the MCP2221: drivers, tools, example code, libraries for JAVA and .NET.


  • USB to serial UART/I2C/SMBus converter
  • Communication Device Class (CDC) for the USB-to-UART option
  • HID class for I2C, control and GPIO options
  • UART with baudrate up to 115200
  • I2C/SMBus with clock rate up to 400kHz
  • 4 general purpose inputs/outputs (can be assigned to other functions).
  • Powered by USB
  • USB Full Speed
  • 3 ADC inputs
  • One DAC with two possible output options
  • External interrupt edge detection
  • UART activity LED output signals (TX and RX)
  • Onboard switch to select the operating voltage (3.3V or 5V).
  • Small size
  • 2 mounting holes




Additional information

Weight 0.010 kg
Dimensions 28 × 21 × 6 mm



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AK-MCP2221 – USB to Serial/I2C/GPIO

Breakout board for the Microchip MCP2221 USB to UART, I2C/SMBus, GPIO converter.


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