Hello, I am using a 8051 Microcontroller development board in which has a 40 Pin P89V51RD2 Microcontroller in it , 4 LEDs connected to its Port 1 , and 4 switches connected to Potr0.
I saw the program "How to interface computer's Serial Port (RS232) with 8051 microcontroller (AT89C51) " in this website, and I burnt the hex file of the above program to my MC. The program worked right with Hyper Terminal Software, but the problem is now I cant erase or re-program my Microcontroller with another program. i.e When I try to burn an another program's hex file, the MC is not responding properly. It throws me an error message as "Unable connect", or "Unable recieve/Send" or sometimes "failled to read device signature". Everytime I tried to burn a new hex file only the 4 LEDs turns On/Off , Even if press the Reset Key nothing happens. I tried lot of ways , but I am not able burn a new hex file.
Please someone help me with this problem. The image of the Dev board I am using is below:
<I am using "Keil u-Vision" for programming, and "Flash Magic" to burn the hex file. >