We are in the process of laying out a new G400-S application specific motherboard. We need a watchdog but also need to be able to disable it while the system is sleeping or at least set a very long (10s of minutes) watchdog period. Reading the SAM9X35 data sheet watchdog section it seems like the hardware doesn’t support a long timeout but the watchdog “can be stopped while the processor is in debug mode or idle mode”
My question is do I hope that future GHI releases will implement some way to stop the watchdog or do I just put an external watchdog on the motherboard? If the later, does anyone have a suggestion for a bullet-proof external watchdog?
If you can’t do this with code in the current libraries, the MAX6369KA allows you to start and stop it via a GPIO pin and you can get long times from it.
@ Gene - The watchdog period is capped at 16 seconds maximum as you probably saw in the datasheet.
We do not currently support putting the processor into idle mode. Through our register class or RLP you can always try to manipulate the registers yourself though to see if you can achieve what you need. You’d have to see if there is an interrupt you can trigger to wake the processor again though.
If you need one that can be disabled for long periods of time, your best bet would probably be to use an external one.