A low power UART design based on asynchronous techniques

Universal Asynchronous Receiver Transmitter (UART) implements serial communication between peripherals and remote embedded systems. The UART protocol is defined based on fixed frequencies with a sampling method to achieve robustness under reasonable frequency variations between systems. Such design specifications are natural for clocked domains. This work investigates whether this simple clocked hardware protocol can be advantageously implemented using asynchronous design techniques. A full duplex clocked and asynchronous UART are implemented and compared. The asynchronous design results in average power of about one-fourth that of the clocked design under standard operating modes.