EMX module supply voltage rise time?

NETMF & Gadgeteer
1

Hi
Does anyone know if there has been defined a maksimum rise time on the 3V3 power supply on the EMX module ?

I have a problem on our new product that it doesn’t start up when the power is turned on slowly. I use a reset IC, that provides a very well defined reset 250ms after the supply voltage has reached 3V3. I have check this with a oscilloscope and it looks perfect - also when it doesn’t start up.

So the processor should be ok, but maybe the other IC’s doesn’t like the slow power supply.

When not starting up, it sometimes it writes a little bit og booting info on the display, but but not always.
(If it gets to show GHI on the top of the screen it always boots up correctly.)

/Søren

2

There is a reset chip built in to the module but I have seen it before where the processor is not happy with slow power rise even with reset held low.