Tom Cassidy wrote:
> Brent, you seem to have hit on the answer!  I reverted to an old version 
> of my code and mixed the setup around a bit, and suddenly it started 
> working!
> 
> I think the trick was putting the ANSEL and ANSELH initialization 
> earlier in the process, but I'm not positive since I moved a lot of 
> things at once. 

Nice you've got it working.
Generelly, I'd probably put the dig/analog settig of the pins
before the init of the peripherials. I don't know why, it just
seems as the logical order in some way... :-)


> 
> I'm new to this site, so if there is any place I should post my working 
> code and/or do something else to contribute to the global PIC knowledge 
> base, please let me know.
> 
> Thank you all for your suggestions,
> Tom
> 
> 
> Brent Brown wrote:
>> On 15 Apr 2009 at 15:43, Tom Cassidy wrote:
>>
>>   
>>> I'm sending the PIC signals through a MAX3232E chip.  I've used the same 
>>> circuit many times, and even with other PIC chips.  And it's working 
>>> fine when the PIC sends a character to the PC.
>>>
>>> When I hook a scope up to the RX pin of the PIC16F690 (Pin 12) I see a 
>>> +5v marking signal as the default, and it spaces to 0 volts as I send a 
>>> character from the PC.
>>>
>>> I should have mentioned that I hooked up the PICkit2 16F887 demo board 
>>> to this same RS232-TTL converter, by removing the '690 from my board and 
>>> jumpering wires from the '887 to the pads.  I used much the same code as 
>>> for the '690.  This circuit worked, sending and receiving characters as 
>>> expected.
>>>
>>> This has really got me stumped!
>>>     
>> Sounds like software like you say. I'd be checking the precise order of initialisation, 
>> and TRIS status for the port lines according to the data sheet. I recently swapped 
>> the order of initialisation routines in a working '886 project thinking it wouldn't hurt 
>> anything - passed my own tests but a while later showed up problems in the field. 
>> Turned out if characters were being received WHILE the USART was being 
>> initialised it would send but not receive (or the other way round, can't remember 
>> exactly) and baud rate was sometimes messed up. It was hard to reproduce the 
>> symptoms, and debugging led me to my own comments in the code... "this 
>> shouldn't affect anything"!
>>
>>   
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