[SOLVED] rs232 serial communcation with 8051

[debabrta kar]

hi i want to do the serial rs232 communication between pc and at89s52 microcontroller... i set it with 9600 baud rate...i just want to know what is time gap between each bit of a rs232 frame...and is it possible if using that much delay i can recieve the frame by connecting the rx pin of computer to any other pin of mcu except p3.0..plz guide me....thanx in advance...

 

[barry]

First of all, there is no gap between bits. If you are asking the time-per-bit, just do some math: 1/9600=104 microseconds. But I'm not sure this is what you really want to know.

Basically, I don't understand your questions. What do you mean by "that much delay"? Can you restate your problem/questions?

 

[afridii]

communication is successfully carried out using some sort of protocols, and the first and necessary objective of the protocol is to synchronize the receiver and the transmitter which is one bit long in rs232 standard, only then receiver of uart at PC can communicate. this whatever you want is possible but before you have to first study the rs232 standard protocol and then transmit you byte serially using other bit but i think it is best to use the built in UART of the microcontroller rather to use other port. The bits have no time gap between them and the bit width is what friend barry told, but
note that since the baud and bit in rs232 is same but not it is not the case in common, generally the baud have 1 or more bits in other communication standards and application.

now its upto you but my advice is to use the rs232

 

[the moon is back]

Hi, one more thing is that, RS232 cable voltage standards does not match with the standard 89S52. For that you need to use MAX232 IC for making RS232 voltage standards compatible with the micro controller.

Thank you.

 

[debabrta kar]

thanx barry.....i have tried with your mentioned logic.....i tried with a 1/9600 = 104 microsecond...and i got my result......and now i am conformed that it is possible tha we can communicate pc with mcu without using the p3.0 rx pin and using any other pin of mcu.....

 

[nandhu015]

thanx barry.....i have tried with your mentioned logic.....i tried with a 1/9600 = 104 microsecond...and i got my result......and now i am conformed that it is possible tha we can communicate pc with mcu without using the p3.0 rx pin and using any other pin of mcu.....

It is called software UART. Check here https://www.8051projects.net/serial-communication/software-uart-8051.php