There can be benefits to using an I2C device instead. One of them comes when using multiple port expander chips. With cascading shift registers you must always shift in the data for the entire ...

[Tech2077] grabbed an I2C port expander that uses just 2 of the RPi lines to address even lines of the display (four data bits plus three control bits). This is a bit of a hack, as the 3.3V logic ...