Controller reset by software?

Hi,

Our ADuC842 (8051 family) based prototype has started to behave 
erratically.  We're fairly certain it's a hardware problem, but before 
building a new print we're trying to rule out software problems.  One 
symptom is random controller resets.  Can this be caused by failing 
software? I'm talking about the effects similar to a complete power 
cycle, not just the PC being reset to address 0.

Thanks,
Walter

"Walter Smits" <wpsmits@hotmail.com> wrote in message
news:4166d23a$0$30777$e4fe514c@dreader16.news.xs4all.nl...
> Hi,
>
> Our ADuC842 (8051 family) based prototype has started to behave
> erratically.  We're fairly certain it's a hardware problem, but before
> building a new print we're trying to rule out software problems.  One
> symptom is random controller resets.  Can this be caused by failing
> software? I'm talking about the effects similar to a complete power
> cycle, not just the PC being reset to address 0.

If you remove most of your code and have just a few simple routines, will
that still continue to happen? Can you get the absolute code minimum where
the problem disappears?

Alex

Walter Smits wrote:
> Hi,
> 
> Our ADuC842 (8051 family) based prototype has started to behave 
> erratically.  We're fairly certain it's a hardware problem, but before 
> building a new print we're trying to rule out software problems.  One 
> symptom is random controller resets.  Can this be caused by failing 
> software? I'm talking about the effects similar to a complete power 
> cycle, not just the PC being reset to address 0.

I think you struck one of their errata already ?
Where there is one, there may be others, not yet fully defined.
Your first RST issue and the trigger conditions can give clues to 
writing small, stimulus test codes.
The 842 is one of a series, so you could also choose a pin compatible
variant, and use that as a HW/SW verify 'second opinion', (even if some
aspects of performance relax).

-jg

Walter Smits wrote:

> Hi,
>
> Our ADuC842 (8051 family) based prototype has started to behave
> erratically.  We're fairly certain it's a hardware problem, but before
> building a new print we're trying to rule out software problems.  One
> symptom is random controller resets.  Can this be caused by failing
> software? I'm talking about the effects similar to a complete power
> cycle, not just the PC being reset to address 0.
>
> Thanks,
> Walter

Watchdog Timing?

>Subject: Re: Controller reset by software?
>From: Neil Kurzman nsk@mail.asb.com 
>Date: 09/10/2004 16:31 GMT Standard Time
>Message-id: <4168ACCC.CBB84C76@mail.asb.com>
>
>
>
>Walter Smits wrote:
>

>> Our ADuC842 (8051 family) based prototype has started to behave
>> erratically.  We're fairly certain it's a hardware problem, but before
>> building a new print we're trying to rule out software problems.  One
>> symptom is random controller resets.  Can this be caused by failing
>> software? I'm talking about the effects similar to a complete power
>> cycle, not just the PC being reset to address 0.
>>
>> Thanks,
>> Walter

Software errors can give the appearance of random failures but the most common
reason for your type of fault is power supply to the chip. Make sure you have
all the recommended decoupling.

Walter Smits <wpsmits@hotmail.com> wrote:
> Hi,

> Our ADuC842 (8051 family) based prototype has started to behave 
> erratically.  We're fairly certain it's a hardware problem, but before 
> building a new print we're trying to rule out software problems.  One 
> symptom is random controller resets.  Can this be caused by failing 
> software? 

That depends on your hardware.  If there's a watchdog timer on your
board, all it takes is a solid deadlock between two parts of the
system, with interrupts disabled, to trigger it and reset your board.

-- 
Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.