ADC on nRF9160 DK - Differential Inputs and more inputs

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

Bjørn Kvaale — Fri, 26 Apr 2019 12:31:52 GMT

Hi Rod,

No clue unfortunately. 😞 I think the best idea is to send an e-mail to your nearest Regional Sales Manager. If you don't know who that is, you can send me a private message on DevZone & I can forward you. Have a nice weekend!

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Wed, 24 Apr 2019 17:13:53 GMT

Hi Bjorn,

Thanks for this, yes that makes sense. So I can now select the single ended ADC inputs so all good.

In terms of getting differential inputs working, do you have an idea of when someone could have a look at this for me?

Thanks,

Rod

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

Bjørn Kvaale — Wed, 24 Apr 2019 14:10:27 GMT

I have asked the developer for help, but unfortunately he is busy with other tasks at the moment. I am not sure when differential ADC measurements will be available. As for this question:

[quote user="RodWatt"][/quote]

I can use either AIN04 or 06 but can not seem to use the others. i.e. AIN0, 1, 2, 3, or 5 on the DK.

I assume these are pre-defined for other uses on the DK. Can I re-assign these?

This is most likely because not all GPIOs are accessible in the nRF91. See this list here for more info.

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Tue, 16 Apr 2019 10:52:54 GMT

Hi Bjorn,

Thank you for the update. In your previous reply, you said you would ask the developer to look at updating the code to support differential inputs. If that is still the plan, Im happy to wait a few days for that. Thanks,

Rod

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

Bjørn Kvaale — Tue, 16 Apr 2019 10:39:49 GMT

Sorry for the delayed response. I have been on a business trip last week & am now on vacation. Due to lower staffing over Easter, there may be some delays in answering questions. DevZone will be fully staffed on the 23rd of April. You can expect a response latest on the 24th of April. Sorry for any inconvenience caused.

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Sun, 07 Apr 2019 11:13:05 GMT

Sorry forgot to mention, I can define the input pin in the lines

#define ADC_1ST_CHANNEL_ID 4

#define ADC_1ST_CHANNEL_INPUT NRF_SAADC_INPUT_AIN4

I can use either AIN04 or 06 but can not seem to use the others. i.e. AIN0, 1, 2, 3, or 5 on the DK.

I assume these are pre-defined for other uses on the DK. Can I re-assign these?

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Fri, 05 Apr 2019 13:13:38 GMT

Hi Bjorn,

Thanks for the offer of help, I will check out the link and see if that helps, if the original developer could help that would be great.

Yes, sorry, I realised that I have been posting code in a clumsy way, thank you for the tip, I will do this in future.

Regards,

Rod

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

Bjørn Kvaale — Fri, 05 Apr 2019 12:42:50 GMT

Good to hear that you figured it out! The objective product specification documentation may be helpful regarding differential ADC, especially Chapter 6.12 SAADC. We do not have a direct example for this yet unfortunately. I can ask the developer who created the ADC example once he is back from vacation. He should be back on the 23rd of April.

This link may also be helpful.

Also, next time, could you please use the Insert -> Code option when pasting a lot of code. This makes it easier for everyone to read. Thanks.

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Wed, 03 Apr 2019 17:34:44 GMT

Hi Bjorn,

Ok, that was the mistake, I should not have changed ADC_0 to ADC_2. So thats working.

The second part of my question, how do I enable differential measurements?

Rod

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Wed, 03 Apr 2019 11:38:27 GMT

Hi Bjorn,

Just had a look at this again, I did change the line

adc_dev = device_get_binding("ADC_2");

I guess this should have stayed ADC_0? I should only have updated the channel ID

Rod

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

RodWatt — Wed, 03 Apr 2019 10:45:52 GMT

Hi Bjorn,

I have not had a chance to try that as yet, but I will try it this evening. Having said that, I would be surprised if this worked. The code above works perfectly for the 1st channel. It's only when I try to move to the 2nd channel that it fails. I would assume if it were the #define CONFIG_BOARD_NRF9160_PCA10090 line that was causing the problem, the 1st channel would also fail?

RE: ADC on nRF9160 DK - Differential Inputs and more inputs

Bjørn Kvaale — Wed, 03 Apr 2019 09:26:22 GMT

Hi Rod,

I believe this may be the same issue as your last case with Martin. Instead of #define CONFIG_BOARD_NRF9160_PCA10090

change this to:

#define CONFIG_BOARD_NRF9160_PCA10090NS

Does that work?