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]

Hi Hakon ,

   Thanks a lot .

Now i got a better clarity  of Nordic "saadc" example.

• Now i want implement this  saadc into our application code. i already told you that we are developing 2d -3d  comp mouse and we are using nRF5_SDK_14.2.0_17b948a  "ble_app_hids_mouse"  application.we modified this application with our own needs.
• I decided to implement adc functionality into our application using TIMER and SAADC module only not using not using PPI.
• Way of working is like below.

1. First we will initialize the  TIMER and SAADC .
2. TIMER is initialized in such a way that ,it will generate an event at every 1 min i.e the execution will enter into the "timer handler function"every 1 min repeatedly.
3. Then inside this "timer handler function" i will 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  
4. After reading the adc data then corresponding led will turn on if the adc result is less than a particular level.

IS THERE ANY ISSUE WITH MY APPROACH ? IF THERE IS  ANY CHANGE NEED PLEASE TELL  ME.