Tag Archives: communication

Using the USART of AVR Microcontrollers.

Welcome to the third part of my RS232 serial communication tutorial. Till now we saw the basics of RS232 communication and made our level converter. Now its time to understand the USART of AVR microcontroller and write the code to initialize the USART and use it to send and receive data. Like many microcontrollers AVR also has a dedicated hardware for serial communication this part is called the USART – Universal Synchronous Asynchronous Receiver Transmitter. This special hardware make your life as programmer easier. You just have to supply the data you need to transmit and it will do the rest. As you saw serial communication occurs at standard speeds of 9600,19200 bps etc and this speeds are slow compared to the AVR CPUs speed. The advantage of hardware USART is that you just need to write the data to one of the registers of USART and your done, you are free to do other things while USART is transmitting the byte. Also the USART automatically senses the start of transmission of RX line and then inputs the whole byte and when it has the byte it informs you(CPU) to read that data from one of its registers. The USART of AVR is very versatile and can be setup for various different mode as required by your application. In this […]