It's likely you've seen some cool Raspberry Pi projects out in the wild — perhaps in the form of digital signage at a restaurant, a retro gaming arcade in a bar, or a smart mirror at a friend's home — ...
More often than not, an IoT master device uses the SPI (serial peripheral interface) and I 2 C (inter-integrated circuit) protocols to exchange data with EEPROMs or sensors that are operating in slave ...