The Figure shows a simple relay RL$1$ connected to an Arduino microcontroller. The system is configured as wireless control door locking$/$unlocking mechanism. The lock mechanism $($not shown$)$ is connected to the relay while the BLT$1$ is a Bluetooth module. The Bluetooth module is connected to a phone $($not shown$)$ to allow the user to control the relay. The Bluetooth module communicate with the Arduino via serial communication.

a$.$ Write the function

yoid systemleit $($void$)$;

to initialise the serial port to operate at $9600$ bps and the digital port D$3\mathrm{.}4$

b$.$ Write a function

unsigned char receiveACharacter $($void$)$;

to wait and recleyst a character $($byte$)$ of data from the seriai port