TRIM.LINCALCOEFF

[AndersG0]

Hello,
read through the documentation about the SAADC and found the TRIM.LINCALCOEFF[n] register.
ADC-linearity is important in the project I'm involved in... 
Seems that the register is available on all 54L devices

Can you share any information how to use it? 

Kind regards, Anders

[Håkon Alseth]

Hi,

 

This is a register that is written to when the driver is initialised.

There will be data copied from the FICR area, which is device specific data, and placed into the driver area, as shown here:

https://github.com/zephyrproject-rtos/hal_nordic/blob/nrfx-4.0.1/nrfx/drivers/src/nrfx_saadc.c#L382-L386

 

This register should not be written to by the application.

 

Kind regards,

Håkon

[AndersG0]

OK, Thanks.
So does that mean that every device ADC is calibrated during production testing?
(Also current engineering samples of nrf54LM20A?)

 Kind regards, Anders

[Håkon Alseth]

Hi,

 

Production grade silicon will be calibrated, while engineering silicon is not guaranteed to be.

SAADC electrical specs are not yet present for the nRF54LM20A device:

https://docs.nordicsemi.com/bundle/ps_nrf54LM20A/page/chapters/current_consumption/doc/current_consumption.html

 

They are however present for the nRF54L15/10/05 devices:

https://docs.nordicsemi.com/bundle/ps_nrf54L15/page/_tmp/nrf54l15/autodita/SAADC/parameters.elec_spec.html

 

Kind regards,

Håkon

[AndersG0]

OK,
I saw the elec-specs for the others.
What is the easiest way to find out if my samples are ADC calibrated or not?
(To initate the ADC and the look at the register content...?)

KInd regards, Anders

[Håkon Alseth]

Hi Anders,

 

There are no official specs for the nRF54LM20A device as of this time. The device in question is still in the engineering phase.

If you require roadmap related information, I would recommend that you contact your local regional sales manager.

 

If you do not have the contact details of your local RSM, please send me a direct message with your location, and I will provide you with this information.

 

Kind regards,

Håkon

[AndersG0]

Thanks, I have the contact details of my RSM, we can close the issue now.

Kind regards, Anders

[AndersG0]

Håkon,
With reference to the above now closed ticket.
After the last communication, I was in contact with my RSM and there will be a new production batch of nrf54lm20a any day now.

Also looked at what is supported in the latest SDK 3.2.3, which I use:
From what I could see, none of the nrf54LXX-SOCs seem to be supported, only nrf54h20_types(.h) and nrf9230_engb_types(.h).
That is, NRF_FICR_HAS_GLOBAL_SAADC_LINCALCOEFF, was not defined for any others...

If I understand the matter correctly, the SDK will need to be updated for the whole thing to work without modification.
Is it in the pipeline to be done soon?

[Håkon Alseth]

Hi,

 

Oh, you are indeed correct! Sorry about that mis-alignment from my side.

The correct placement for the nRF54L-series devices is in the system file:

https://github.com/zephyrproject-rtos/hal_nordic/blob/master/nrfx/bsp/stable/mdk/system_nrf54l.c#L141-L142

 

If calibration is required, the loading from ficr to the appropriate peripheral will be included.

 

Kind regards,

Håkon

[AndersG0]

Thanks a lot!
As newbie to both the 54L and the "zephyr / nrfConnect" environment,
its interesting to get a little bit under the bonnet and understand how things work. 

[Håkon Alseth]

Hi,

 

Happy to help out!

AndersG0 said:

its interesting to get a little bit under the bonnet and understand how things work. 

If you are interested in how the RTOS works, I can recommend looking at our dev academy:

https://academy.nordicsemi.com/

 

The quiz after each exercise is quite educational.

 

Kind regards,

Håkon