pic hanging

[ssaakmnt]

I wrote this simple control routine and it was working fine most of the time,
some times it get stuck and do not execute at all

[ckielstra]

The PIC hardware is so simple that it is quiet difficult to make it 'hang'. The most likely problems when the processor hangs:
1) There is an interrupt not being cleared and the processors stays in the interrupt loop.
2) You programmed an endless loop.
3) Power supply problems.
4) The processor goes into Low Voltage Programming mode when pin B3(PIC16) or B5(PIC18) goes high.

Option 4 is not implemented in your processor, and option 1 is not in your program. That leaves 2 & 3, of which number 2 is the most likely.

I didn't look into your code as it is difficult to follow. Please use an extra level of indentation for every '{}' block. That also means you can never put two '}' characters on the same line.

A second remark on your program is that your elevator system is a classical example for code to be implemented with a State Machine. Using that design pattern your code will become easier to understand, and from easier understanding automatically a better program will result with fewer bugs.
Please search the internet for a detailed explanation on what State Machines are and how to implement them.

[Mike Walne]

Could be noise from your motors causing code to go off somewhere not intended.

I also don't care to analyse your code.

You could include a WDT, but that doesn't answer the question of what's happening.

I'd be adding some diagnostics, allows the PIC to tell me what it thinks it's doing.

That way you can find out if the failure is truely random, or always from the same or a similar point.

Mike

[temtronic]

To follow up on Mike's 'noise' issue, replace the motors with LEDs.
Quick, simple visual indicators that will NOT generate 'noise' that could crash your program.

Another source of 'noise' could be your 'floor switches'. All mechanical switches need some form of 'debounce', either hardware (R-C networks) or software (timers).

You could also reduce your code to say 2 floors, get it working, then add floors, testing each addition of code.

hth
jay

[asmboy]

Failure of a sensor to "sense" would do it.

I would NEVER have so many while(1) statements w/o some form of escape other than the sensor.
You might consider a timer based emergency exit from each of those while(1) CONSTRUCTS using say a timer overflow?

A var set to a unique value could be used to tell which loop is failing to exit when the timer saves the day....

[ssaakmnt]

Thank you guys for your responses. I will consider all information. I suspect the problem from sensor because it always stop there and it sometimes escapes sensor to stop on the next one. So its probably from sensor endless loop i miss to note.