using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Tue, 24 Oct 2023 14:46:25 GMT

my power profiler shows i am pulling 800 ua in the power off state.. this is due to other chips on my custom board and I will be getting a new board.. so I would like to close this case until i get a new board. then i will open a new ticket.

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Mon, 09 Oct 2023 08:29:42 GMT

Ok, remember to isolate the current so that whatever you measure is only the current drawn by the nRF5340,

regards

Jared

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Mon, 09 Oct 2023 03:56:51 GMT

i just got a PPk2 power profiler kit. i wll have some hard numbers soon.

thanks

phil

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Tue, 19 Sep 2023 09:31:48 GMT

Yes,

In system off you'll get into the deepest possible power saving mode of the nRF5340. System off is not the same as system on sleep (commonly referred to as IDLE). In System Off the nRF5340 has only a couple of wakeup source, the amount of current that is consumed depends on what wakeup source that is configured and if RAM is retained or not. I think you need to isolate the current that is used by the nRF5340 and measure it. That would tell us a lot about what state the chip is in.

Also, see the power section in the product spec.

regards

Jared

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Mon, 18 Sep 2023 16:40:49 GMT

i have a custom board with some know current leakage but when I add things up i still see between 100-200 ua of unexplained current draw. i am trying to track it down. so if i go to system OFF on nrf5340 both the network core and the application core are not running the processor is still alive because it can wake up. and VDD is at 1.8 volts. if i go to SYSTEM off and easy DMA or BLE was running you are saying that they will stop. is this correct ? i want to rule out the processor as the source of my mystery current loss.

thanks

phil

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Tue, 12 Sep 2023 08:05:02 GMT

Hi Phil,

If you go to system off then all peripherals will be disabled automatically including the EasyDMA. In the same screenshot from the product spec that you shared it says: System OFF is the deepest power-saving mode the system can enter. In this mode, the system's core functionality is powered down and all ongoing tasks are terminated.

regards

Jared

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Mon, 11 Sep 2023 20:45:20 GMT

The last line in the document shown below talks about making sure easy DMA is off before going into system off mode.

i am wondering why. in system off move the HFclock will stop and that means easy DMA will stop. I am not retaining any ram so i do not care if easy DMA stops in mid transfer.

sorry to be so picky but my boss wants all the bases covered.

thanks

phil

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Mon, 11 Sep 2023 09:14:08 GMT

Hi,

Could you point me to the documentation that states this?

regards

Jared

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Sat, 09 Sep 2023 16:25:30 GMT

i am not worried about consuming current. my boss said he needed a mode to get the system off as soon as possible. the documentation says to turn off easyDMA before i call nrf_regulators_system_off(NRF_REGULATORS);

and i do not understand why. if the HF clock is going to be shutdown why would i worry about easyDMA?

i guess my fundamental question is what bad thing could happen if easy DMA is not shut down?

thanks

phil

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Thu, 07 Sep 2023 12:44:37 GMT

Hi,

In system off, all peripherals will be off including the EasyDMA. If you're worried about the nRF5340 still consuming current, then I would suggest to measure the current that is consumed by the nRF5340, that would tell us a lot.

regards

Jared

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

weightwatcherphil — Wed, 06 Sep 2023 17:22:24 GMT

we have a custom board and PPK2 says 800 ua. Most of the current is due to external circuitry which we are addressing but i want to make sure since i am using zephyr ADC driver that i have the saadc turned off before i go to system off mode.

in system off mode there are no clocks so it should be off but the manual says EasyDMA has to be off. I was looking for a function to turn off the saadc and did not find it.

thanks

for your help

phil

RE: using C:\ncs\v2.4.0\zephyr\samples\drivers\adc on nrf5340. do i have to uninit the saadc

Jared — Wed, 06 Sep 2023 10:46:26 GMT

Hi,

The SAADC peripheral use EasyDMA so any driver that is implemented for this peripheral will therefore also use EasyDMA.

What current do you measure at the moment?

regards

Jared