Why there is some data duplicated during rs232 communication

young · Joined: 24 Jun 2004 Posts: 285

My Rs232 communicated well, but with a problem, that is sometimes, it output more result than I expect, like

printf("%u \r\n",data);

the hyperterminal print out \0A 234 \0D
occasionally print out \0A 234 234 \0D, or \0A 234 4\0D.

what might cause this problem?

young · Joined: 24 Jun 2004 Posts: 285

I put a delay after printf; it looks everything is fine. maybe I am seding data too fast?

IN low baud rate, I need a long delay, in high baud rate, may not need delay, it depends.

Haplo · Joined: 06 Sep 2003 Posts: 659 Location: Sydney, Australia

Is your printf() in a loop? Post more of your code.

young · Joined: 24 Jun 2004 Posts: 285

Thank you: here is the main ()

Haplo · Joined: 06 Sep 2003 Posts: 659 Location: Sydney, Australia

Well I'd say you were pumping out data so fast the the PC was missing characters. That made it look like duplicated data. A delay should take care of it as you said.

For int32 also use %lu.

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

This isn't the first post where you have had problems with receiving chars to your PC. I'd look at the connections, MAX232 chip, cable, or even try another PC. And don't use Hyperterminal, in sucks!

MGP · Joined: 11 Sep 2003 Posts: 57

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

I just cannot believe that Windows still includes it!

CharlieGill · Joined: 29 Nov 2004 Posts: 15 Location: northeast georgia

Thanks for the tips on a Hyperterminal replacement. I've never liked it but have just been to lazy I guess to go looking for a replacement.

I downloaded Bray Terminal as TeraTerm had it's last update in 99. I grinned when I saw the VT100 support. I wonder how many people these days even know what a VT100 was...ah the good old days. Well I guess they probably wern't all THAT good, 4K, asembler, cassettes, TV monitors, yuk. Still I miss the light and switches of the old control panels sometimes.

Charlie