nRF51822 - After power up, program does not start without cycling the reset pin.

RE: nRF51822 - After power up, program does not start without cycling the reset pin.

Mahonroy — Mon, 26 Nov 2018 23:13:32 GMT

I figured out what the problem was. I had to insert a "nrf_delay_ms" command in my initialization function... looks like it was booting up too fast before all the other circuitry on the circuit board was ready (other IC's using I2C, UART IC, etc.). This is why manually resetting always worked, because everything was already powered up.

RE: nRF51822 - After power up, program does not start without cycling the reset pin.

Mahonroy — Mon, 26 Nov 2018 18:29:38 GMT

Hello, thank you for the response.

This unfortunately did not fix the problem. This allowed the program to start running after flashing.... but disconnecting the J-link and just powering up the device itself, the firmware doesn't start without manually resetting it by shorting SWDIO to ground... at which point it starts working.

RE: nRF51822 - After power up, program does not start without cycling the reset pin.

Håkon Alseth — Wed, 21 Nov 2018 15:02:12 GMT

Hi,

Sounds like your project setting is not running the firmware after flash download.

Here's how to verify this setting:

https://devzone.nordicsemi.com/f/nordic-q-a/963/why-hard-power-reset-is-needed-after-every-flash-into-nrf51822

Could you try this and report back?

You could also use nrfjprog for this: nrfjprog --pinreset -f nrf51

Best regards,

Håkon