How can I change VDD to 3.3v

[Geass77]

I want to change vdd to 3.3v , but when I use the code showed in picture, it remain error

[Vidar Berg]

Hi,

Is the chip fully erased before this code is run? Also, what is the problem you are experiencing? Is it that it fails to build or update the register setting?  

[Geass77]

It fails to build , so I need to erase all the chip first? 

[Vidar Berg]

Thanks for confirming. Unfortunately, it won't help to erase the chip as this is a build error. What is the error you get?

NRF_NVMC->CONFIG should already be accessed in your startup file (system_nRFxx.c) to enable PINRESET. Are those routines being compiled without errors?