8-bit MicrocontrollersのトピックRe: SCI/UART Loopback problem with QE32

SCI/UART Loopback problem with QE32

Exelsus — Wed, 22 Jul 2009 03:49:02 GMT

Dear Friends,

I wrote some SCI/UART interrupt driven routines to handle Tx and Rx of data and place them into circular buffers, the problem is that every character I send is received back. The LOOPS bit in the SCI1C1 register is not set, and there is no physical connection between the pins.

I can see all this in debug time, the Rx buffer is getting filled inmediatly after the Tx sends any character, i think someway the Tx is raising the Rx interrupt flag.

I'll attach the source code in hope some of you can help me pointing me in the right direction, I have 2 days trying different things but nothing has worked yet, I don't know what to do.

Thanks

(I'm not currently using getQuery() as I've not managed to get the Tx working without have the loopbacks)

Re: SCI/UART Loopback problem with QE32

Exelsus — Wed, 22 Jul 2009 04:59:37 GMT

Updates:

I implemented the same code into a QG8 (with a little translation of course) guess what, exact same problem...

Now the question is: What am I doing wrong?

I'll attach the sources and whole project in the QG8 as it is only dedicated to that problem.

Thanks

Whole_Project.zip

Just_the_Sources.zip

Message Edited by t.dowe on 2009-10-27 11:42 AM

Re: SCI/UART Loopback problem with QE32

Exelsus — Wed, 22 Jul 2009 12:21:51 GMT

I think i solved it for now...

Recomendations:

1) Pullups/Pulldowns are your friends (Even when the outputs are NOT open drain kind)

2) Homemade PCB sucks to some degree, try to get OCD while working with them.

3) Flux can be a bitch after soldering, especially when pins are so close to each other.

This was more like a blog, I just hope it can be useful for someone.