Hi friends, i am new to this forum, i have encountered a problem, i want to send the serial data from PC to 8051 micro controller through serial port and hyper terminal software, but the data is not receiving by micro controller. I want to display the character on 16 x 2 LCD display. RI is not setting to 1 and the routine what i written to receive and display the character is not executing. I am using Flash magic software to dump the code into micro controller and it is going properly.

Since one week i am facing this problem, earlier it worked properly(data displayed on LCD). I attached my code and circuit diagram, so please suggest me what to do.

 

Don't you need to set the REN (Receiver ENable) bit in SCON?

 

Thanks for your reply. I set the bit REN bit in SCON reg, that's why i put the scon value as 0x50(10010000). last two bits 1 0 are for mode 2, and the next 1 is for REN. I always set the bit REN to 1. Is this correct sir, please suggest me what to do.

 

From your circuit, it shows a 12 MHz crystal being used. I supposed you are programming for 9600 bps. However, using a 12 MHz crystal, you will have a 8% error on the baud rate. I am not sure if this is the cause of your non reception. You can try changing the crystal to 11.0592 MHz which will give a more accurate 9600 bps.

Alternatively, you can lower the baud rate to 2400 bps using the 12 MHz crystal. 12 MHz can produce a baud rate of 2404 bps. The error reduces to 0.2%.

 

Thanks for your reply, i will try with 11.0592 crystal...