This is basic example on how to send and receive one character over AVR UART peripheral. We can divide UART related program lines in few sections. 1-UART, 1-SPI, 1-I2C. Power Debugger is a powerful development tool for debugging and programming AVR microcontrollers using UPDI, JTAG.

Till now we have seen the basics of RS232 communication, the function of level converter and the internal USART of AVR micro. After understanding the USART of AVR we have also written a easy to use to initialize the USART. That was the first step to use RS232. Now we will see how we can actually send/receive data via rs232. As this tutorial is intended for those who are never used USART we will keep the things simple so as to just concentrate on the 'USART' part. Of course after you are comfortable with usart you can make it more usable my using interrupt driven mechanism rather than 'polling' the usart.

So lets get started! In this section we will make two functions:- • USARTReadChar(): To read the data (char) from the USART buffer. • USARTWriteChar(): To write a given data (char) to the USART. This two functions will demonstrate the use of USART in the most basic and simplest way. After that you can easily write functions that can write strings to USART.

Reading From The USART: USARTReadChar() Function. This function will help you read data from the USART. For example if you use your PC to send data to your micro the data is automatically received by the USART of AVR and put in a buffer and bit in a register (UCSRA) is also set to indicate that data is available in buffer. Its now your duty to read this data from the register and process it, otherwise if new data comes in the previous one will be lost. So the funda is that wait until the RXC bit (bit no 7) in UCSRA is SET and then read the UDR register of the USART.

PL2303 based USB to USART Module Finding the COM port number of Serial Port A PC can have several COM ports, each may have some peripheral connected to it like a Modem. Serial Ports on PC are numbered like COM1, COM2 COMn etc. You first need to figure out in which COM port you have connected the AVR.

Download The Observer Sky Atlas Pdf Software. Only after you have a correct COM port number you can communicate with the AVR using tools such as Hyperterminal. The steps below shows how to get COM port number in case of Virtual COM Ports. Right Click on 'My Computer' icon in Windows Desktop.

COM Port Number Communication using a Terminal Program on PC. Since this is the introductory article about serial communication, we won’t be going in much detail on PC end COM port programming.

For this reason we will be using a ready made software for sending and receiving serial data. I will be showing how to use two different terminal program to exchange data with embedded application. Windows Hyperterminal This is a default terminal program shipped with Windows OS. You can start it from Start Menu->All Programs->Accessories->Communication->Hyperterminal. Hyperterminal is not available in Windows Vista or Windows 7 so you have to use other terminal programs like RealTerm. On startup it will ask for a connection name.