[En-Nut-Discussion] UART Ethernut3 stop receiveing bytes after a while

[ml]

Hi Alain,

thank you for the hint. i test it only with 19200 Bauds so it´s rather slow
for such a fast cpu.
the problem isn´t completely solved when i disable debugging feature - it
only appears much later.
maybe it´s an reentry problem. It doesn´t matter if i send the char back to
the same uart or
to another device like my lcd display. for now i can ignore the problem
because i really not 
need the echo, but i think that points to a problem in (nut/gcc or ?) and
such kind of problems 
will reapear later whe you never need them. I will try to find out the
reason for this to avoid later 
problems. 

Martin


Alain M. wrote:
> 
> Hi Martin,
> 
> even being new to Nut/OS, I am in the RS232 thing for a loooong time. I 
> would bet that you are having re-entry problems. Let's say that because 
> of the debug option, the next char gets delayed up to a point that the 
> next will renter the last one or that the sending char overrides the 
> last. This could lead to one interrupt accurring while the last is 
> running and if not properly coded this can cause problems.
> 
> You can try 2 things:
> 1) run the same test at much lower speeds so that you can discard some 
> bug related to the debug part, then repeat it at very high speed with no 
> debug just to see if it happens too
> 2) send a known sequence and test it at the receiver side, you can then 
> split the problem between receiving/sending/debugging.
> 
> Alain
> 
> ml escreveu:
>> Solved a bit :( 
>> 
>> if i build nutos without debug infos all work´s well. for now it´s a
>> solution, but i wonder how this happens.
>> in debugger i can see that the irq is never called again but the
>> register´s
>> are set correctly. i test with 
>> the UART-loop in a thread. The main thread is still running after the
>> mistake. The debugger sometimes tries to reach a breakpoint but want´s to
>> examine a memory-adress far behind the physical memory - seems to be
>> random. 
>> 
>> Martin
>> 
>> 
>> 
>> ml wrote:
>>> Hi,
>>>
>>> i run into a problem with uart. the small loop in the example produce an
>>> echo at the 
>>> uart. Uart is initialized in normal Mode without handshake and so on.
>>> If i type in some characters in the terminalwindow all is ok. But if i
>>> transmit short
>>> strings from pc with full speed after a while the receiver isn´t working
>>> anymore.
>>> In debugger i can see that the sig_UART Interrupt is never called again.  
>>>
>>> when i put in the nutsleep instruction  it works for hours. 
>>>
>>>    NutRegisterDevice(&DEV_UART0, 0, 0); 
>>>    com1 = fopen(DEV_UART_NAME, "r+b");
>>>
>>>    for(;;) {
>>>   //   NutSleep(20);
>>>      if ((c=fgetc(com1)) != EOF) {
>>>        fputc(c,com1);
>>>        fflush(com1);
>>>      }
>>>    }
>>>
>>> any help for this strange problem ?
>>> ENUT 4.4.0  with Eclipse and openocd
>>> Martin
>>>
>> 
> _______________________________________________
> http://lists.egnite.de/mailman/listinfo/en-nut-discussion
> 
> 

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