ADC Conversion using 4096Hz for nRF52832 Chip?

[vishal]

Hello Sir,

We are using nRF52832 chip and Softdevice is S132. Is it possible to sample an analog signal using internal ADC conversion using 4096Hz?. Its look like it does at 3900Hz.

Thanks in Advance..

[Jørgen Holmefjord]

I don't know how you have setup RTC, but you should make sure you do not enable interrupt if you want to trigger the sampling through PPI. You also need to clear the RTC after getting the compare event. This can also be done using PPI. I will edit my answer above with a working main.c file for ble_app_uart__saadc_timer_driven__scan_mode that implement sampling using RTC over PPI. Note that you need to include the nrf_drv_rtc.c source file, and enable RTC in sdk_config.h.

[Jørgen Holmefjord]

How do you measure the current? If 5 mA is your average current consumption with only advertising, this seems quite high. switching to RTC for sampling should not increase your current consumption. Do you have approximately the same sample rate with both setups? The EasyDMA current (~2mA) enabled with the SAADC could be limited by disabling the SAADC between samples, as shown in the low power SAADC example, but with your samplerate, you might not gain much on this either. Could you upload your applications for debugging?