TI’s MSP430 chips are rather interesting – they’re low power, very capable, and available for under a dollar in most cases. Some of these chips, though, don’t have native SPI or I2C interfaces; instead, everything is done through a USI, or Universal Serial Interface module. [Jan] found the stock I2C USI module was a little rough around the edges, so he created his own.
[Jan] found the TI example code for using the USI as an I2C device overly complicated and something that an intern whipped up in a week and was never touched again. In response to this, he created a much, much simpler USI/I2C module that’s actually readable. It’s available over on the GitHub if you want to grab it for yourself.
Compared to the TI code, [Jan]’s library is dead simple. There are only two functions, one for initialization, and another for sending and receiving. Easy, small, and it works. Can’t do much better than that.