Selective sampling of ADC channels at run time

[SChary]

I am using a 52810 custom board and the SAADC module.

It is used for sampling one analog input through AIN2 and the battery voltage directly by setting the pin to VDD

As per the documentation, since more than one channel is configured/enabled, it goes into scan mode.

i need to measure the analog input at AIN2 for 15 seconds.

However, i do not need to measure the battery voltage in every scan. I only want to measure it once every 5 seconds to check for voltage drop.

Is this possible ?

Regards

Chary BS

[SChary]

Hello Einar,

I see that this ticket is still not closed from your side. Luckily, I had another query about the SAADC usage

Continuing in the same thread, i wanted to ask how to do the following, in terms of initializing and un-initializing the ADC and its channels

In my system, as mentioned earlier, i have to capture the signal at AIN2 and the battery voltage, but not simultaneously.

So can I do nrfx_saadc_channel_init() and nrfx_saadc_channel_uninit() as and when required ? Will there be any resource fragmentation issues with that ?

Do i have to check for ADC busy or idle state before calling uninit or is it taken care internally?

Thanks in advance

Chary BS

[Patrick]

Take a look at my ticket here, where I discovered that channel configuration is reset by the driver, causing readings to be incorrect. Channel configuration will need to be applied prior to sampling with the V2 driver due to the way the registers are reset internally to the driver due to a high power consumption workaround.

[SChary]

Hello Patrick,

Thank you for the reference! I have still not moved to the V2 api, am using the older version itself and am testing to see if there are any quirks....

Regards

Chary BS