Hardware hacking, part 3: using my 5V FTDI cable on 3.3V UARTs without killing the board

Part 3 of 7 in the Hardware hacking series. Part 1: updating the firmware on a Pinecil V2. Part 2: the bench I work on. My USB serial cable has an FTDI FT232RL in it and is sold as a 5V cable. Most router and IoT consoles run their UART at 3.3V, a few at…