nrfx_saadc_irq_handler not getting triggered

[john.ashok]

Hi ,

I am using saadc to measure battery voltage i m using the sample example given as reference ble_app_proximity/

I am doing adc_configuration in one file and triggering nrf_drv_saadc_sample() from different file in this case alone  nrfx_saadc_irq_handler is not getting triggered

if i call the nrf_drv_saadc_sample() from same file everything is working fine.

Could you help me identify why this is happening?

SDK version  15.2

nRF52840

[john.ashok]

Actually I an trying to call adc_configure in bas notification enable event if i do that it doesn't return any error but i didn't get 

nrfx_saadc_irq_handler.

So is it wrong to call adc_configure inside ble event?

[Karl Ylvisaker]

Hello John,

john.ashok said:

Actually I an trying to call adc_configure in bas notification enable event if i do that it doesn't return any error but i didn't get 

nrfx_saadc_irq_handler.

So is it wrong to call adc_configure inside ble event?

I am not sure I understand what you mean here, are you trying to put the SAADC configuration and init function into the bas_init function?
If not, which function are you inputting the SAADC config and init calls into?

Could you possible share the snippet of code in which you are doing this?
If you could also confirm that you are passing the returned error codes from the SAADC functions to an APP_ERROR_CHECK that would be very helpful. Please also make sure that you have defined DEBUG in your preprocessor defines.

There should not be any issue calling the SAADC functions as part of the bas_init function.

Looking forward to resolving this issue together!

Best regards,
Karl

[john.ashok]

I m not calling it as part of bas_init() i am calling it in the BLE_BAS_EVT_NOTIFICATION_ENABLED event

static void bas_evt_handler(ble_bas_t * p_ess_service, ble_bas_evt_t * p_evt)
{
uint32_t err_code;
(void)p_ess_service;
switch (p_evt->evt_type)
{
case BLE_BAS_EVT_NOTIFICATION_ENABLED:
// Start battery timer
battery_level_update();
break;

case BLE_BAS_EVT_NOTIFICATION_DISABLED:
break;
default:
// No implementation needed.
break;
}
} 

int8_t battery_level_update(void)
{
ret_code_t err_code;
static bool is_adc_configured = false;

if (!is_adc_configured)
{
err_code = adc_configure();
is_adc_configured = true;
if (NRF_SUCCESS != err_code)
{
return -1;
}

}
err_code = nrf_drv_saadc_sample();

while (!adc_transfer_done)//updated in adc_event_handler
;

*bat_status_percent = batt_status_percentage;
*bat_status_mv = batt_status_in_milli_volts;

if (NRFX_SUCCESS == err_code)
{
return 0;
}
return -1;
}

[Karl Ylvisaker]

Thank you for clarifying.

What is the content of your adc_configure function?
Is the error code it returns one returned by for example saadc_init, or channel_init?
If so, why are you not passing it to an APP_ERROR_CHECK? This would let you know if it failed.
In general, you should always pass a returned error code to an APP_ERROR_CHECK, and then rather implement specific error handling in the APP_ERROR_CHECK, rather, if that is desired.

I think your problem here lies with the line while (!adc_transfer_done)//updated in adc_event_handler.
Here, you are already in an event handler, and you are asking to wait in the event handler for another event handler to finish processing.
What is the interrupt priority of the SAADC?
I suspect that the SAADC's interrupt priority is equal to or lower than the BAS event - which ensures that the SAADC can not interrupt the BAS event, and thus the BAS event can not complete.
I recommend that you do not make these kinds of while waiting loops within event handlers, it is not an advisable practice.

Furthermore, you might be waiting forever here either way, since you are not checking the error code of the nrf_drv_saadc_sample call - which might have failed. If it fails, you will not know about it, and be stuck forever waiting for the sampling to complete.

Please remove this, and see if it resolves your issue.

Looking forward to hearing if this resolves your issue! 

Best regards,
Karl

[john.ashok]

adc_configure() calls these functions  saadc_init(), saadc_channel_init() and saadc_buffer_convert() and it returns success 

nrf_drv_saadc_sample() also returns success but event handler is not triggered at all 

I have configured the priority like below

#define NRFX_SAADC_CONFIG_IRQ_PRIORITY 6 

#define BLE_BAS_BLE_OBSERVER_PRIO 2

as you said if i call this adc_configure()  and nrf_drv_saadc_sample()  other than bas event it works

Also after configuring and reading my first ADC sample if i call nrf_drv_saadc_sample()  in bas event it works as expected the adc event is getting triggered

whether the priority issue comes only for first sample?