Hi, I am trying to implement serial communication from my real time hardware system. I have developed my source code KEIL and verified using serial software simulator of KEIL. I am getting perfect result. But when I am trying to implement on the real time hardware system I am unable to get the desired result. I am using the real time hardware system with a baud rate of 2400bps. Can anyone please explain what could be the possible reason.
regards. raghun
Hello Andy or whoever you are!!!!
You can not make exact 9600 Baud with a 24MHz crystal, the Baudrate wouldn't be exact. The architekture of 8051-UART don't allow this.
If you believe, that you have managed this task, then your wellcome to post your code.
"You can not make exact 9600 Baud with a 24MHz crystal, the Baudrate wouldn't be exact."
Not exact, but close enough (+0.16% error).
PCON |= 0x80; // Set double-rate bit, SMOD TMOD &= 0x0F; // Clear Timer 1 control bits, upper nibble, in TMOD register TMOD |= 0x20; // Put Timer 1 in 8-bit, auto-reload mode (Timer 1, Mode 2) TH1 = 0xf3; // Define Timer 1 reload value RCLK = 0; // Define Timer 1 as the UART receiver baud clock (T2CON.5) TCLK = 0; // Define Timer 1 as the UART transmitter baud clock (T2CON.4) TR1 = 1; // Enable Timer 1 as baud-rate generator (TCON.6)
Check it out at: http://www.keil.com/c51/baudrate.asp