MCU land, part 9: ST7789, the final frontier

In some of my earlier articles dealing with “bare metal” microcontrollers, I talked about the process of interfacing them to modern graphic display modules. This task remains a bit of a mystery to hobbyists: there are few tutorials dealing with anything more modern than the text-based HD44780 LCDs from the 1980s. When graphics are needed, it’s common to reach for a Linux-based system-on-a-chip, or to rely on questionable third-party libraries that use the woefully slow I2C protocol.