RE: Using a counter via PPI to count pulses on a pin

ovrebekk — Wed, 14 Nov 2018 10:10:30 GMT

Hi Steve

That is interesting. Typically it is only bit 31 that should be set. This is the PORT event, which is usually used for button detection by the button library.

You might find that buttons will no longer work if you clear this bit ;)

Can you try to read the register before you clear it, using the debugger?

Then you should see which bits are set originally.

As a general comment I would strongly suggest using the defines in nrf52_bitfields.h rather than using magic numbers for the registers. Then your code is more easily readable:

NRF_GPIO->PIN_CNF[31] = GPIO_PIN_CNF_SENSE_Low << GPIO_PIN_CNF_SENSE_Pos;
NRF_GPIOTE->CONFIG[6] = GPIOTE_CONFIG_MODE_Event << GPIOTE_CONFIG_MODE_Pos |
31 << GPIOTE_CONFIG_PSEL_Pos;

Best regards
Torbjørn

RE: Using a counter via PPI to count pulses on a pin

SteveHx — Tue, 13 Nov 2018 11:58:31 GMT

I have added this line to my configuration function:

NRF_GPIOTE -> INTENCLR = 0xFFFFFFFF;

and now everything works as it should. That tells me that somebody enabled one or more interrupts on that port. Everything appears to now be working nicely, including the BLE stack. But what have I turned off that is going to bite me later?