Effects of CPU blocking due to BLE radio on ADC sampling frequency and Workaround

RE: Effects of CPU blocking due to BLE radio on ADC sampling frequency and Workaround

Jared — Fri, 29 Apr 2022 13:23:22 GMT

[quote user="bryanhsieh"]

To achieve low power with scan+burst+oversample, it seems like resetting the ADC is the only way.

[/quote]

Are you thinking about cases where the EasyDMA is still running after disabling the ADC?

[quote user=""]From the table taken from the documentation on BLE radio blocking time during advertisement shown below, it seems the maximum blocking time is 128us.[/quote]

The maximum blocking time for one advertising event would be the marked formula with the max parameters:

If you want a window where it can guarantee that you wont be interrupted then I would suggest using Radio Timeslots.

regards

Jared

RE: Effects of CPU blocking due to BLE radio on ADC sampling frequency and Workaround

bryanhsieh — Tue, 26 Apr 2022 16:46:42 GMT

Thanks Jared, I had a look at the example, it doesn't fully cover what I what to do or answer all of my questions.

To achieve low power with scan+burst+oversample, it seems like resetting the ADC is the only way.

I am not too sure if I can do this with the ADC driver and hence the code shown above directly set/control the ADC registers.

Also I wanted to check if the radio blocking time would adversely affect adc when sampled @256Hz.

RE: Effects of CPU blocking due to BLE radio on ADC sampling frequency and Workaround

Jared — Tue, 26 Apr 2022 12:48:54 GMT

Hi,

Can you take a look at our ble_app_uart__saadc_timer_driven__scan_mode example?

regards

Jared