How to read One Time Programmable (OTP) memory in nRF9160?

[Chetan Kale]

Hello Team,

I am facing segmentation fault while reading the OTP memory using pointer in my code. To write the OTP value I have used below command which was successful and also I am able to read OTP section using the read command given below.

$ nrfjprog --memwr 0xFF8108 --val 0xAABBCCDD

$ nrfjprog --memrd 0xFF8108 

But when I try to dereference the address using below code it throws me a segmentation fault. 

#define CLOUD_MODULE_ID_ADDR 0x00FF8108

main()
{

uint32_t DeviceID = *((const uint32_t *)CLOUD_MODULE_ID_ADDR); 

printk("Device ID: %d\n",DeviceID);

}

Do I need any special permission to read the OTP section? Because, I could not found any article which talks about how to read the OTP memory for nrf9160. 

Kindly, support me to overcome this issue asap.

Thanks in advanced. 

Regards,

Chetan

[Håkon Alseth]

Hello,

 

UICR (and FICR) is secure only, so you have to use this function to access the data:

https://github.com/nrfconnect/sdk-nrf/blob/v1.7.0/include/secure_services.h#L88

 

However, the function does not allow you to read the UICR area, only FICR area:

https://github.com/nrfconnect/sdk-nrf/blob/v1.7.0/subsys/spm/secure_services.c#L79-L82

 

If you patch the above array with:

		{.start = NRF_UICR_S_BASE,
		 .size = sizeof(NRF_UICR_Type)},

 

Then you should be able to read the whole UICR region with this function.

 

Kind regards,

Håkon

[Chetan Kale]

Hello Håkon,

Thanks for the quick response. I am able to read the UICR region using the above steps which you mentioned. 

Regards,

Chetan

[Håkon Alseth]

Hi Chetan,

 

Chetan Kale said:

Thanks for the quick response. I am able to read the UICR region using the above steps which you mentioned. 

That is great to hear! I hope you have a wonderful day!

 

Cheers,

Håkon