Controlling XM power on and shutdown


I am investigating the feasiblity of a XM for a project I'm working
on. I'll be using the XM as a non-critical web and database server.

I need to be able to shut it down gracefully from an arduino in a
power failure (where I will have both running off a battery); and then
power it back on when power resumes.

But I can't see any power switch headers! Is there a way to do this?

Also, is wake-on-lan supported?

There is indeed a power switch function brought out on the MMC expansion header called PWR_CNTRL (Figure 26 of the System Reference Manual) that connects to the PMIC that can be used to power down the board, but SW will need to be written as it is currently not supported that I know of. This may or may not perform your desired function. There are other components on the board that may not be able to be totally controlled by this function (such as LDOs), so it also depends on how much power you want to get down do. Obviously using a relay to totally remove the power is also an option that is shall we say, total in its ability to remove power.


Thanks - the main reason I'm looking to do a 'graceful' shutdown is to
avoid data corruption by suddenly cutting power. I can use the linux
shutdown/halt command to do that.

I had a look at the xM manual (which is what I'm thinking of using)
and it looks like it might function as a regular momentary power
switch - like on an ATX case/mobo. That would be perfect. I can
switch that and then use a relay after a delay...

You can always use a GPIO pin as an interrupt to the processor and then use that launch the code for the graceful shutdown. In essence the pin I directed you do does exactly that if the PMIC is programmed correctly.


Brilliant - thanks. I will buy an XM as soon as I can find someone
with stock... has stock and by the end of the month most everyone will have stock as well. D/K receives weekly shipments but they do not show stock as long as they have backorders to fill, so don’t hesitate to buy from them as well.