Electric Imp imp API uart.flush() example

flush.device.nut

// Assign parallel aliases for the UART according to role
arduino <- hardware.uart57;
computer <- hardware.uart57;

function relay() {
    // UART initially configured for Arduino input
    local byte = arduino.read();

    if (byte != -1) {
        // We have a valid byte to relay so reconfigure the UART
        // for output to the computer. Remember: disable arduino first
        server.log("Switching UART to computer...");
        arduino.disable();
    
        // Configure UART for computer connection and write byte
        computer.configure(115200, 8, PARITY_NONE, 1, NO_CTSRTS);
        computer.write(byte);
    
        // With the byte sent to the computer, reassign the UART
        // back to the data source, Arduino, and await next byte
        server.log("Switching UART to Arduino");
    
        // Flush the FIFO first to make sure the byte has been sent
        // before we disable the computer link
        computer.flush();
        computer.disable();
    
        // Configure the UART to read from Arduino
        arduino.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS, relay);
    }
}

// Initialize by starting to read from Arduino
server.log("Switching UART to Arduino");
arduino.configure(9600, 8, PARITY_NONE, 1, NO_CTSRTS, relay);