void writeByte(char data) {
    int parityBit = 1;
    high(_dataPin);//set pin high
    high(_clockPin);//set pin high
    delayMicroseconds(300);
    low(_clockPin);//set pin low
    delayMicroseconds(300);
    low(_dataPin);//set pin low
    delayMicroseconds(10);

    // start bit
    high(_clockPin);
    waitForClockState(LOW);
    // data
    for (int i = 0; i < 8; i++) {
        int dataBit = bitRead(data, i);
        writeBit(dataBit);
        parityBit = parityBit ^ dataBit;
    }
    
    // parity bit
    writeBit(parityBit);
    
    // stop bit
    high(_dataPin);
    delayMicroseconds(50);
    waitForClockState(LOW);

    // wait for mouse to switch modes
    while ((digitalRead(_clockPin) == LOW) || (digitalRead(_dataPin) == LOW))
        ;
    // put a hold on the incoming data
    low(_clockPin);
}