When the data is written to UDR it will be transferred to Transmit Data buffer register and when we read the contents of the Receive Data buffer register is returned. In this there are two shift registers referred to as Transmit Shift register and Receive Shift register with each having a separate buffer register. UDR or USART Data Register is meant for writing and receiving the data through the UART. Lets see the functions of these registers briefly. In AVR there are five registers which are meant to use for Serial Communication such as UDR, UBBR, UCSRA, UCSRB, UCSRC.

REGISTERS USED IN AVR SERIAL COMMUNICATION: As we all know Microcontroller works in TTL logic which is not compatible with the PC so we have to employ a level converter IC MAX232, read more about the working of IC MAX232. Serial.read() Reads incoming serial data Serial.println(val) Serial. To re-enable serial communication, call Serial.begin(). The above design demonstrates the usage of UART to send and receive data via hyperterminal as well display the received data in 1 16×2 LCD. Serial.end() Disables serial communication, allowing the RX and TX pins to be used for general input and output. UART plays an important role in almost every embedded applications which we see in our day to life and hence it was considered to be very important concept in every Microcontroller. This tutorial focuses to teach you how to program AVR Serial Communication (UART).

Uart serial communication pdf