SAADC in polling mode instead of interrupt/callback

[himanshu pande]

Hello,

Can the SAADC driver be modified to be used in a polling mode instead of interrupt?

E.g. I modify the driver to not use any interrupt(comment out interrupt enabling calls). And then in a periodic task(thread)

Sample pseudo code below

int16_t buffer[5];

void Task_5ms()

{

if(NRF_SAADC.EVENTS_RESULTDONE == 1)

{

nrf_drv_saadc_buffer_convert(&buffer, 5)

for (i = 0; i < 5; i++)
        {
            //Retrieve elements from buffer[0] through buffer[4]
        }

}

}

Will this approach work? The reason to do it as we need as few interrupts in system as possible for safety reasons.

Best Regards,

Himanshu.

[Kenneth]

Hello,

Have you checked out:
https://www.nordicsemi.com/DocLib/Content/SDK_Doc/nRF5_SDK/v15-2-0/hardware_driver_saadc?96#saadc_blocking 

Best regards,
Kenneth

[himanshu pande]

Hello Kenneth,

Blocking mode is understood. Thanks. But is there any scenario in blocking mode that would trigger SAADC interrupt?

If the interrupt is not going to be used, I can comment the code in SAADC init:

//NRFX_IRQ_PRIORITY_SET(SAADC_IRQn, p_config->interrupt_priority);
//NRFX_IRQ_ENABLE(SAADC_IRQn);

Right?

[Kenneth]

I do notice that nrfx_saadc_sample_convert() is calling nrf_saadc_int_disable() on entry and nrf_saadc_int_enable() on exit. So I think you may need to comment out those also, but I assume it should work yes. The easiest may just be to comment out NRF_SAADC->INTENSET and NRF_SAADC->INTENCLR in nrf_saadc.h.

[himanshu pande]

Thanks Kenneth

[Steven Bauer]

The SAADC driver can be modified to be used in a polling mode instead of interrupting. This is done by changing the SAADC driver to be configured as a polling driver. This means that the SAADC driver will only be activated when the polling mode is enabled slope unblocked. This is useful for situations where a polling mode is required but the SAADC driver is not required to mapquest driving directions. For example, a polling mode may be required for a polling application but the SAADC driver is not required.