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???
05/16/05 22:36
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#93507 - A couple of things.
Responding to: ???'s previous message
Jim Peterson said:
Hi

I new to this world of microcontrollers but have succeeded in building a pcb using a 87c52 with external eprom and sram which will flash a LED. Now I'm on to trying to get the serial port up and running in a polled mode and have done alot of reading about these sfr registers: SCON,TCON,and TMOD as well as the TH1,TI and RI bits

I have selected a 11.0592mhz crystal which according to my calculations gives a even number of 250 to set the baud rate at 9600 with.

My serial_init function looks like this:

SCON=0x50;
TMOD=0x11;
TCON=0x52;
TH1=250
TI=1;
RI=0;

It looks like you're going for 8-bit serial transmission using timer 1 in 8-bit auto-reload mode for baud rate generation.

That said, the first thing I notice is that your TMOD initialization is wrong. Try this:
TMOD |= 0x20
Good luck.

--Sasha Jevtic

List of 9 messages in thread
TopicAuthorDate
setting SFR registers            01/01/70 00:00      
   A couple of things.            01/01/70 00:00      
   Change it to C!            01/01/70 00:00      
      why            01/01/70 00:00      
      but it already is C!!            01/01/70 00:00      
         Mehdi probably meant:            01/01/70 00:00      
            Yes Jan            01/01/70 00:00      
   Baud rate            01/01/70 00:00      
   *what* doesn't work?            01/01/70 00:00      

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