[Avila] watchdog on avila (GW-2348)

[starman986]

Additional note on watchdog + JTAG programmers:

Most JTAG programmers have a script file that loads when connecting to the target. To make third party JTAG work with the watchdog resistor loaded modify your JTAG startup script to write the following values right after reset:

location 0xC8004018  value 0x01FF01C6
location 0xC8004004  value 0x00003FF7

The first line makes GPIO14 a clock, the second line enbles
GPIO14 as an output.  See IXP425 Programmers Guide for more details.



--- On Fri, 4/11/08, Tim Harvey <tim_harvey at yahoo.com> wrote:

> From: Tim Harvey <tim_harvey at yahoo.com>
> Subject: Re: [Avila] watchdog on avila (GW-2348)
> To: "Sebastian G" <sebastian.gra at gmail.com>
> Cc: avila at lists.gateworks.com
> Date: Friday, April 11, 2008, 2:18 AM
> Sebastian,
> 
> Just to be clear - all you need to do to utilize the
> hardware watchdog is to load the resistor (a solder-blob
> will do) and add the software to strobe it.  I do agree
> that the 'standad' product should have the watchdog
> ready to go.  I'm not sure why the resistor is not
> loaded on the GW2347 as it does no harm to have it loaded
> and not enable the watchdog strobe buffer via software.  As
> for the 2348, I wish Gateworks had run the strobe through a
> GPIO controlled buffer as they did in the 2347 and then
> loaded the resistor by default.
> 
> Having a hardware watchdog doesn't make any difference
> between indoor and outdoor equipment (because a unit is
> outdoors doesn't make it any more prone to software
> bugs).  In my experience/opinion you should always have a
> hardware watchdog, esp if your running a modern day OS with
> so many codepaths you can never be certain you don't
> have software bugs that will cause a device to
> hang/malfunction.
> 
> Tim
> 
> ----- Original Message ----
> From: Sebastian G <sebastian.gra at gmail.com>
> To: Chris Lang <chris at ccbw.net>
> Cc: David Acker <dacker at roinet.com>; Tim Harvey
> <tim_harvey at yahoo.com>; avila at lists.gateworks.com
> Sent: Friday, April 11, 2008 12:07:32 AM
> Subject: Re: [Avila] watchdog on avila (GW-2348)
> 
> 2008/4/11, Chris Lang <chris at ccbw.net>:
> > To All,
> >
> >  I will just piggy back on what Tim said...
> >
> >  The internal IXP watchdog is not adequate on these
> boards to use as a
> >  watchdog as it doesn't reset flash, as stated, if
> it is used, you will
> >  experience boot problems if the watchdog resets
> during a flash read or
> >  write.
> >
> >  The reason the IXP42x watchdog is not used is that
> there was a bug in the
> >  silicon of the IXP42x when this was designed that
> made the watchdog hang the
> >  CPU upon a reset, hence the reason why other IXP
> hardware is configured the
> >  same.
> >
> >  The external watchdog can be used, but as Tim said
> can be difficult to
> >  strobe from as you have to strobe it once a second.
> We, Gateworks, configure
> >  GPIO14 from within redboot as a 4.7mhz clock which
> strobes the watchdog
> >  adequately but only protects against processor
> lock-ups, not from software
> >  lock-ups, typically not what you want. It has been
> noted that attempting to
> >  strobe the watchdog with a heartbeat has a high
> percentage chance of
> >  failing, and has seen to fail when the board comes
> under heavy load.
> >
> >  The resistors are not loaded by default on the GW2348
> series because there
> >  is not an ability to enable/disable the watchdog. If
> the resistor is loaded,
> >  you have to strobe the watchdog, or the board is
> unusable. The loading of
> >  the resistors is an ordering option for 100pc min
> purchases.
> >
> >  There is also issues with programming the boards
> through jtag with the
> >  watchdog resistor loaded, this has been resolved with
> the DOS version of our
> >  utility, but no other jtag programmers/debuggers
> currently work with the
> >  resistor loaded.
> >
> >  Thanks,
> >
> > Chris Lang
> >  clang at gateworks.com
> >
> 
> ok, thank you all for the help. Now it is all clear for me.
> It just
> looks like the avila boards are not to well for any outdoor
> use if
> they do not have a proper watchdog on board ready to use.
> 
> Best regards,
>     Sebastian.
> 
> 
> 
> 
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