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]

Hi,

If you trigger sampling through PPI on an RTC event, it should be possible to achieve 4096 Hz. The RTC runs at 32.768 kHz, and a CC value of 8 should give you your desired frequency. If you are triggering sampling from interrupt event, the softdevice might delay sampling if higher priority events occurs, giving you a lower sample rate than expected.

Note this issue if you are triggering sampling through PPI, and have multiple SAADC channels enabled.

[EDIT]: Added main.c file that implements sampling triggered by RTC over PPI in ble_app_uart__saadc_timer_driven__scan_mode example: main.c

Best regards,

Jørgen

[vishal]

I check in my sdk_config.h RTC0 is not enable RTC2 is enabled, now when i remove lfclk_config(void) function device is advertising and also connect with my phone. But when i sent command for start saadc my ADC value is not received in my apps, means no any data sent from nordic to UART. As per you refer me this above example in this no any PPI channel use. Can you tell me how i trigger PPI on RTC. In my code i use saadc_sampling_event_enable(); in main. my application is read 3-axis accelerator analog value one by one channel. Thanks sir......