Enable APP Protection Fails

[Ronny L]

Hi,

I'm working on enabling APP Protection while successfully executing below code:

if (!nrf_sdh_is_enabled()) {
     if (VERSION_BUILD <= MAX_RELEASE_BUILD) {
         NRF_UICR->APPROTECT = 0xFFFFFF00;
     }
   }

 

Please advise why I'm still able to read out the flash afterwards via the SWD interface.

Best Regards,

Ronny

[superpak]

Are you sure the NRF_UICR->APPROTECT register is being written to with your above code? I think you need to set the NVMC controller in write mode before you can write anything to the UICR registers.

Maybe try the following:

/* Turn on flash write enable and wait until the NVMC is ready: */
NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos);
while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}


/* write to the register */
NRF_UICR->APPROTECT = 0xFFFFFF00;
while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
    
/* Turn off flash write enable and wait until the NVMC is ready: */
NRF_NVMC->CONFIG = (NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos);
while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}

[Ronny L]

Thanks, this helped and works.