SAADC channel input select/nRF52832/

RE: SAADC channel input select/nRF52832/

Pertti Kasanen — Tue, 28 Jun 2016 15:18:03 GMT

Darren, at least I was earlier running on old SDK11 alpha version. With that it is not possible to use the ADC properly, but it worked all right with Rev C when upgraded the SDK (and SoftDevice, which in our case was not trivial from alpha).

RE: SAADC channel input select/nRF52832/

WestCoastDaz — Tue, 31 May 2016 04:19:08 GMT

Nordic is PAN-28 fixed in Rev B,C and Rev 1 silicon as I currently have NRF52_PAN_28 defined in my build? I am using Rev B and C for pre production and Rev 1for production. My application requires scanning of the ADC channels and I would prefer to have the ADC do this than emulate it with interrupts.

RE: SAADC channel input select/nRF52832/

Pertti Kasanen — Tue, 03 May 2016 15:40:21 GMT

Oh, it seems that this PAN 28 fis is still in the library. I have nRF52 Engineering C HW in use. But it seems that cannot use the SAADC fully. Without fixing the libraries manually?

I'm now trying by modifying the nrf_drv_saadc_channel_init() to end with nrf_saadc_channel_input_set(channel, p_config->pin_p, p_config->pin_n); Hope that is enough...

RE: SAADC channel input select/nRF52832/

Susheel Nuguru — Tue, 07 Jul 2015 13:14:57 GMT

OK, good luck, please accept this answer, so that we can move on :) please update this thread if possible with your observations later on.

RE: SAADC channel input select/nRF52832/

maddy5075 — Tue, 07 Jul 2015 13:01:52 GMT

Right on Aryan. The function nrf_drv_saadc_buffer_convert() does that and the example provided does that too. Thanks for your time and the clarification. Will let you know the result of the test once i get access to DK/EK.

RE: SAADC channel input select/nRF52832/

Susheel Nuguru — Tue, 07 Jul 2015 11:57:15 GMT

I think the pins are enabled one you call nrf_drv_saadc_buffer_convert. So I think your application will work anyways. Let me know if it works without any change

RE: SAADC channel input select/nRF52832/

maddy5075 — Tue, 07 Jul 2015 11:32:25 GMT

What if an application has to use AIN0 as an ONE and ONLY analog input pin and configure it to run in continuous mode and not the scan mode ?

With the SAADC driver function nrf_drv_saadc_channel_init(

uint8_t channel, nrf_saadc_channel_config_t const * const p_config), if one has to configure the channel 0 with default configuration, the above said function despite initializing the SAADC with the user provided input, will eventually disable the AIN0 by setting its PSELP as NC (not connected).

So all the above configuration which the driver function nrf_drv_saadc_channel_init() does becomes futile. The fix is to call nrf_saadc_channel_input_set(channel, NRF_SAADC_INPUT_DISABLED, NRF_SAADC_INPUT_DISABLED) before nrf_saadc_channel_init(channel, p_config) unless there is a genuine reason for doing so to have a work around for the Errata.

The example provided in nRF52832 might work, since it is sampling Vdd pin.

I will check to see if the driver function works correctly with no modification after having access to DK/EK. If it doesn't i will seek further directions.

RE: SAADC channel input select/nRF52832/

Susheel Nuguru — Tue, 07 Jul 2015 10:40:05 GMT

This seems related PAN 28 infocenter.nordicsemi.com/.../anomaly_832_28.html

Looking at the code it looks like they are disabling the input and scanning each line by enabling each channel individually to emulate a scan mode in the interrupt handler SAADC_IRQHandler.

This will go away when the PAN is fixed.

RE: SAADC channel input select/nRF52832/

Susheel Nuguru — Tue, 07 Jul 2015 07:59:02 GMT

looks strange, i will investigate it.