While the Raspberry Pi has very good support for an I2C bus, a lot of very cool chips – including the in system programmer for just about every ATtiny and ATmega microcontroller – use an SPI bus.
Near 60 FPS video playback on a 2.4" SPI TFT (ILI9341) using a Raspberry Pi Zero 2 W with a heatsink. SPI at 52 MHz, optional spidev.bufsiz tweaks, overclocking, and Python with OpenCV, PIL, and ...