A13 watchdog timer

[David Goadby]

The A13 has a 20 second watchdog timer. AFAIK this has to be enabled by building the u-boot with CONFIG_WATCHDOG enabled. Does anyone know what the current Olimex A13 release watchdog configuration is?

Ideally, a watchdog that can be enabled by a root application once the system has completed start-up is better so my guess is that it is not enabled as standard. The safe option would be to enable the watchdog but set the time to 0 which effectively disables it until a time is set.

Before I start re-building kernels has anyone used the A13 watchdog? What is the location to "poke" to reset/enable it?

I am about to have a "play" with the A13 in Linux mode so may answer my own question later... ;-0

David Goadby

[bernard]

I never played with it, but I think this is a very important topic for "industrial" applications. I hope we have a good solution. (I am after an Android deployment). I will be following this closely.

[David Goadby]

I agree. In fact all of my control systems use a watchdog of some form. If we cannot get at the existing watchdog on the A13 then this is my plan (A)..

The GPIO-1 interface on the A13 has power, 4 I/O bits and a signal called RESET_N. The I/O lines are part of the AXP209 power chip but there is an I2C interface so I assume we can use them. The RESET_N line needs investigating as the signal says "PWROK" on the AXP209 chip so this may not be a reset line as in "pull down = CPU reset". It might be a line to indicate that the CPU is resetting or is not ready. If it is not waht is required then the RESET switch has the line we need.

If the pins we need on GPIO-1 are usable then I will make the watchdog as a UEXT module with a simple device like the Maxim MX6373 on it.

As for Android I need to have a closed application which is easier and cheaper to do in Linux. That said, the Android touch screen interface on the A13 works well already and Android apps are easy to create so I too have been looking at it. I did find a package that locks up Androids in what they call "kiosk" mode where you can control user access to the home screen and also manage auto-startup apps. The software was called SureLock but costs $49.99 per unit ($29.90/10) so a small ouch! I have to make 50 units for my first customer job using the A13 and the extra $$$ per unit soon adds up. ;-)

Regards

David Goadby