RS-232

younus_noman · Joined: 04 Jul 2005 Posts: 9

I am trying to receive data serially over RS-232 through LAB VIEW.

Lab view sends 3 bytes plus a termination character (0D ) at the end to PIC16f876 controller. Some how i am not able to read that termination character (0D) using getc().

Is it necessary for me to send a carriage return and a line feed at the end to read the 4th termination character?

Any ideas?

Noman Younus

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

getc() does not do any filtering or exclusion of characters.

See the test program below. It receives a character with getc()
and then displays it as a hex value in the terminal window.
When I type "ABCD" into my terminal program and press
the Enter key on my PC, I get the following output:

younus_noman · Joined: 04 Jul 2005 Posts: 9

Thanks for your quick reply..

I tried the above code before and i am able to display the hex value.

but when i say printf("ABCD \r\n") it displays ABCD on the hyper terminal whereas if i say printf("ABCD") without using the line feed and carriage return then it just displays ABC i.e. it chops of the last byte and i am not sure y it does that

I also did PIC to PIC commnication and displayed the recevied data on my LCD.

MASTER PIC sends---- printf("ABCD \n\r);
SLAVE PIC receives and displays ABCD

If i receive 6 bytes it displays ABCDAB (using getchar)

Thanks

Noman Younus

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

You must have a while(1) in your main. Most likely you do not, just the printf and nothing after that. What happens is that main finishes and there is a hidden sleep instruction in there. The last byte of data is still in the transmit buffer when the pic goes to sleep. Post your program if you don't understand what I am talking about.