Disabling saadc problem

[asombredance]

I am using nrf52832, SDK14 and sd 132.5.0. I want to disable SAADC after measuring battery level then enable again when I want to measure it again like in this post. When I try to do that it resets device every time in this handler.

static void battery_level_meas_timeout_handler(void * p_context){

    UNUSED_PARAMETER(p_context);

		static int i=0;
	if(i!=0) //don't initialize twice at the beginning
	{
		nrf_drv_saadc_init(NULL, saadc_event_handler); 
	}
	i=1;
	
    ret_code_t err_code;
    err_code = nrf_drv_saadc_sample();
    APP_ERROR_CHECK(err_code);

	
	nrf_drv_saadc_uninit();

	
	NVIC_ClearPendingIRQ(SAADC_IRQn);

}

How can I solve this problem? Also I am using DFU in my application(May it cause?). This way is working in blinky example, but in my application it resets.

[Jørgen Holmefjord]

Hi,

I'm not sure I understand your code. If you uninit the SAADC driver after sampling, you need to init it again before next sample. What is your i=0;, if(i!=0) and i=1; code suppose to do?

Most likely you are trying to call nrf_drv_saadc_sample when the SAADC driver is not initialized, which will return an error code. When you pass a non-zero error code to APP_ERROR_CHECK, the default recovery method is to reset the chip. Please use this debugging method to check the returned error codes in your application.

Best regards,

Jørgen

[asombredance]

At the beginning I called nrf_drv_saadc_init(NULL, saadc_event_handler) when I was doing configuration in the main. In this question you said "Most likely you get an error code because you are trying to initialize a module that is allready initialized ", so I tried to make it pass initializing part for the first time handler runs.

[Jørgen Holmefjord]

You need to check the error codes. Use the method I linked above, and make sure you check the error code from all function calls:

ret_code_t err_code;
err_code = nrf_drv_saadc_init(NULL, saadc_event_handler);
APP_ERROR_CHECK(err_code);

[asombredance]

I used debugging method, the error code is 0x00000008 for err_code = nrf_drv_saadc_init(NULL, saadc_event_handler).

[Jørgen Holmefjord]

0x08 means NRF_ERROR_INVALID_STATE. If you get this from the init function, the SAADC driver is already initialized. You should use a flag that you set when init is called and clared after uninit, to keep track of the state. Another thing is that you can't call uninit right after calling the sample function, as this will uninit the driver before sampling is completed. You need to move the uninit function to the SAADC callback.