RS232 doesn't work me well

[Roberto Serra]

I, my name is Roberto,

this is the first time I write in a forum, so sorry if this is the second time that someone ask help fot the same problem, but I looked in the Historical event list and Ididn't find the answare for my question...


I'm using Flowcode 4.2.3.58 and a pic18F6722.
I built all the code for my programand it working, but when I introduced the RS232 and started Hiper-Terminal on the PC, the comunication doesn't work well.

The Recived Characters are different from the otiginal.... why?

What have to change??

the bit Rate is 4800 for all but the recived caracters was different, I really don't know why...

Someone can help me??

[Steve]

This can happen when the baudrate of the RS232 on the chip is different to that set in Hyperterminal. You should check your settings. Also, make sure the chip is running at the frequency you think i is running at (the easiest way to do this is to write a simple LED flasher to confirm the rate of flashing).

[Roberto Serra]

Hello, I follow your suggestion.
RS232 is set to 9600 and the HyperTerminal too.
The transmission was recived but not always was good.
I try to change the boud rate with a little difference (9595-9605) but the best results are with 9600.
For the clock I'm using a 10MHz quartz oscillator, without PLL Frequency Multiplier; I tried to use the 4x internal Frequency Multiplier but the results was the same... (the capacitor are 22pF like the datasheet indication)...

I don't know how to solve this problem....

[Benj]

Hello

You could try enabling the Flow control to see if this helps. Otherwise please can you attach your program and the C code that is generated and I will take a look and see if I can spot whats gone wrong.