Low power pulse width measurement with LPCOMP


I'd like to be able to use an event from the LPCOMP to sample the RTC (either to a peripheral's register, or to a memory address), so I can measure pulse widths without waking the processor.

Is there any way of doing this? It seems like EasyDMA might be an option, but as far as I can tell it only appears to be built into peripherals, not usable as a standalone memory transfer device.

Ideally I'd just use a timer, but it seems they have to run off the high speed oscillator, not the low speed one? Or is it possible to use the TICK event from the RTC to increment a timer? Is that efficient, or does it then need to start the high speed oscillator 32k times a second?