RE: Reading a GPIO bus

hmolesworth — Thu, 17 Mar 2022 15:46:19 GMT

You can synchronously read all 32 bits of the input port P0 simultaneously with a single instruction. Using a bit mask and shifts enables cuddling up the data bits if that is required. An advantage of using a single 32-bit read returns not just the data bits but also the sync etc bits. Since the input port sampling clock is 16MHz the race hazard/uncertainty between fast changing input pins can be estimated.

 volatile uint32_t inputPinSnapshot = NRFP0->IN & pinsDefinedAsInputsMask;