I’m trying to put my imp into deep sleep until a tilt switch gets triggered by motion. But unfortunately, the wakeup pin appears to be level-triggered, so if I have bad luck and the device is oriented with the tilt switch ON, the imp cannot sleep. While I could build an external flipflop circuit or differentiator to fix this, and allocate a second pin for the actual tilt switch signal, this is still drawing extra power, requiring extra circuitry and using up a pin.
Would it be possible to allow the wakeup pin to be user-configured as an edge triggered interrupt? Or is there already a way to do this?
Only going high triggers and I think it’s down to the processor so can’t be changed. I have a pir triggering mine it will sleep event if pin is high, But let us know if you have flip-flop that works there are a few of us would like to wake the imp on rising or falling edge.
Many processors (including the Imp’s ARM Cortex M3) have a software selectable option for edge vs. level triggering on a per-pin basis. I was hoping someone could expose that register in a supported fashion, if the Imp has it.
The imp’s particular processor doesn’t have a selectable option for the wake-from-deep-sleep pin: it’s level-triggered only, unfortunately. This is a hardware limitation.