DOUBT IN SAADC EXAMPLE FROM SDK V 14.2.0

[NANDHU]

HI,

       We are developing a 2d -3d  mouse with nRF5_SDK_14.2.0_17b948a  "ble_app_hids_mouse"  application.

• For knowing the battery discharge rate of our product we are trying to implement adc into our code "modified ble_app_hids_mouse ".  
• We are using p0.02(AIN0) for measuring  the battery status.
• Actually our requirement is ,we want to check battery level(i.e adc value) at regular interval of time (may be 1m) and if the battery level is less than 20% we will turn on yellow led and if the battery level is less than 5% the red led will turn on.

For configuring the ADC , I look yours saadc code but i have some doubt in your code .

• I think  in your saadc code they configured ADC ,TIMER AND PPI.

I will explain the flow of code execution what i understood from your saadc below if there is any mistake please correct me

• TIMER will generate an event every 400ms .
• By the help of PPI a task was occurring in SAADC peripheral   due to TIMER event . and its repeating at regular intervals (400 ms)

1. "saadc_callback" function will execute when there is a TIMER event occur , is it right?
2. During the initialization part(saadc_init) "nrf_drv_saadc_buffer_convert" function is calling and also inside the  "saadc_callback" function   is "nrf_drv_saadc_buffer_convert" function is calling . I known these function is for  issuing conversion of data to buffer. Then why its calling on both "saadc_init"  and  "saadc_callback" function.
3. From which buffer we can read the converted analog to digital data ?

please answer to my 1,2 and 3

 if you need any clarification in my question please ask me .

[NANDHU]

Thanks Hakon now all issues was solved ,now all the five values are almost equal and also its varying according to the voltage variation from the power supply .

Now i needed your help to implement the adc to our custom application.

I ready told you that, what's my approach  is.

•  I decided to call the  saadc functions for starting the saadc sampling i.e nrf_drv_saadc_sample and for read the adc result i.e  nrf_drv_saadc_buffer_convert  inside the timer handler  function.
• But the problem that . How can i verify that the adc conversion is  finished or not .Is there any function for that ?