MCP2221 HID Library

This is a library for interfacing with the HID features of the MCP2221 USB to UART and I2C/SMBus serial converter from Microchip. The converter includes 4 GPIO pins, 3x 10-bit ADCs, 1x 5-bit DAC and more.

Microchip does provide a library for interfacing with the chip, however it is supplied as proprietary DLLs. This project aims to be an open-source and multi-platform alternative.

This library also makes use of HIDAPI.

| Feature | Status | ------- | ------ | ADC | Supported | DAC | Supported | GPIO | Supported | Interrupt input | Supported | Clock reference output | Supported | USB Descriptors (Manufacturer, product, serial, VID, PID) | Supported | I2C/SMB | Limited support, WIP | Flash password protection | Not yet implemented | C++ and C# wrappers | Not yet implemented

Documentation

Doxygen pages

Hint:

| Function prefix | Description | --------------- | ----------- | mcp2221_set* | Set SRAM config, this takes immediate effect | mcp2221_get* | Get SRAM config | mcp2221_save* | Writes to flash, this setting is used at startup | mcp2221_load* | Read from flash | mcp2221_read* | Read ADC/GPIO/interrupt values

Setting up

Using pre-built binaries

• Copy libmcp2221.h to your compilers include directory (/usr/include/ on Linux)
• Windows: Copy ./lib/win/libmcp2221.dll to your compilers lib directory. Each program that uses libmcp2221 will need a copy of libmcp2221.dll in the same directory.
• Linux: Copy ./lib/unix/libmcp2221.so and ./lib/unix/libmcp2221.a to /usr/lib/ (these were compiled on Debian 8.4 x64 using the HIDRAW version of HIDAPI)

Compiling

• Download hid.c for your OS from https://github.com/signal11/hidapi (Windows | Linux (HIDRAW) | Linux (LibUSB - this doesn't seem to work at the moment) | Mac) and hidapi.h
• Place hid.c and hidapi.h files into the libmcp2221 directory
• Linux HIDAPI requires dev packages for libudev and libusb apt-get install libudev-dev libusb-1.0-0-dev
• Run make
• Copy libmcp2221.h to your compilers include directory (/usr/include/ on Linux)
• Windows: Copy libmcp2221.dll from the bin folder to your compilers lib directory. Each program that uses libmcp2221 will need a copy of libmcp2221.dll in the same directory.
• Linux: Copy libmcp2221.so and libmcp2221.a from the bin folder to /usr/lib/

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Third party contents are copyrighted by their respective authors.

My productions are published under GNU GPL v3 (see License.txt).

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MCP2221 HID Library

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Zak Kemble

contact@zakkemble.co.uk