CONFIG_GPIO_AS_PINRESET doesn't work

[Juan Moya]

Hello,

I didn't put this define CONFIG_GPIO_AS_PINRESET and I configure the PIO.21 as output and the micro has a reset by this pin.

[gamnes]

Hi,

I will assume you are running on the nRF52832. CONFIG_GPIO_AS_PINRESET is working fine. In our SDK examples, for example ...\nRF5_SDK_14.2.0_17b948a\examples\peripheral\uart\pca10040\blank\arm5_no_packs\uart_pca10040.uvprojx this can be tested and seen in the terminal.

Start with the standard SDK example as is, compile and flash this to the DK. Open a serial terminal to its com PORT (baudrate 115200). Reset the board using the reset button on the DK or power cycle, and then in the terminal you will see the print "Start:". Now if you take a jumper cable and connect P0.21 to GND (for example SB17 is P0.21), you will see the device restarts and the terminal prints "Start:" again.
Now if you take away the define CONFIG_GPIO_AS_PINRESET from the project, recompile. Erase the entire flash of the DK using 'nrfjprog --recover' - IMPORTANT: its important to erase the entire flash because the Pin Reset settings are stored in UICR, and they are not necessarily erased when you click Load in the IDE! Flash the newly compiled application which does not define GPIO as PINRESET. Reopen the terminal, and reset the board, you should now see "Start:" be printed, but if you connect the same jumper to P0.21, no reset will happen.

The reset button on the DK will work regardless of the reset button being enabled or not, but it will just perform a Soft reset instead of Pin reset if the Reset GPIO is not configured/enabled. 

DK hardware description: http://infocenter.nordicsemi.com/pdf/nRF52_DK_User_Guide_v1.2.pdf.