parity bit, DCD, DSR, DTR or RI signals. The implemented UART is not fully 16650 compatible, but all control bits for simple UART receive/transmit operations are still available. With RxD and TxD signals, basic communication with measurement instruments (oscilloscope, frequency meter) is possible through the UART/RS232 interface. The ARM BCM2835 unit needs a 3.3V power supply, also the GPIO lines, including UART, are compatible only with 3.3V. To assure compatibility with the RS232 standard, an additional UART/RS232 converter was used (MAX3232 dedicated specially for a 3.3V supply).