Sending and Receiving Data Serially to/from PC.

Sending and Receiving Data Serially to/from PC.

Description: Parallel communication is fast but it is not applicable for long distance (for printers).

Moreover it is also expensive. Serial is not as much fast as parallel communication but it can deal with transmission of data over long distances (for ex telephone line ADC, DAC).It is also cheaper and requires less physical wires that’s why we use serial communication.

Methods of Serial Communication.

There are two methods of serial communication

1)Synchronous: Transfer the block of data between sender and receiver spaces by fixed time interval. The transmission  is synchronized by an external clock.

2)Asynchronous: There is no clock involved here and transmission is synchronized by special signals along the transmission medium.

It transfers a single byte at time between sender and receiver along with inserting a start bit before each data character  and a stop bit at its termination so that to inform the receiver where the data begins and ends.

3)USART: Universal Synchronous/Asynchronous Receiver- Transmitter it uses external clock .So it needs separate line to carry the clock signal.

4)UART : Stands for Universal Asynchronous Receiver - Transmitter it generates its internal data clock to the microcontroller it synchronizes that clock with the data stream by using start bit transition. Receiver needs band rate to know time.