SAADC will not start

RE: SAADC will not start

hmolesworth — Thu, 09 Jan 2025 15:27:53 GMT

You can't set a high priority when using Zephyr or any other OS. Change the 1 to 6 and see if that helps. There are lots of examples for interrupts in Zephyr.

Change:
  NVIC_SetPriority(SAADC_IRQn, 1);
to:
  NVIC_SetPriority(SAADC_IRQn, 6);

RE: SAADC will not start

Taylor Nelson — Thu, 09 Jan 2025 15:18:44 GMT

Thankyou,

I am still having trouble with interrupts though. I noticed that the specific line that is causing problems is

    NVIC_EnableIRQ(SAADC_IRQn);

whenever this line is included in my code, my board will constantly reboot itself over and over. Getting rid of this line causes the board to not reboot itself, but the interrupts are still never triggered.

From what I have seen from other information online, since I am using nRF Connect for VS Code, Zephyr is automatically included in the build, and that interrupts need to be configured differently when using Zephyr.

Do you have any information on how to configure the interrupts for a build with Zephyr?

Best,

Taylor

RE: SAADC will not start

hmolesworth — Wed, 08 Jan 2025 21:22:22 GMT

Don't clear IRQn in interrupt, but that's another issue. Depending on compiler, interrupt vector handler must be an exact name match to be called as a vector instead of the default handler. Only END interrupt is enabled, so don't waste time testing it. Use a DSB instruction to avoid problems later on.

void SAADC_IRQHandler(void)
{
    ADC->EVENTS_END = 0;
    // In case the code is later modified with no following instructions prevent a spurious extra interrupt
    __DSB();
    printk("ADC Value: %u\n", adc_data_buf[0]);
}

Use volatile keyword:

static volatile uint16_t adc_data_buf[1]; // Single sample buffer

RE: SAADC will not start

Taylor Nelson — Wed, 08 Jan 2025 16:26:39 GMT

Thank you,

That solved the issue of getting out of the infinite loop: while(!ADC->EVENTS_STARTED), but the interrupt is still not being triggered at all.

Is there anything that I am doing wrong in terms of setting up the interrupt?

I modified the IRQ to the code below, and I never see "Interrupt Called" printed to the console, so I know that the IRQ is never executed.

void SAADC_IRQHandler()
{
    printk("Interrupt Called\n");
    if(ADC->EVENTS_END)
    {
        ADC->EVENTS_END = 0;
        printk("ADC Value: %u\n", adc_data_buf[0]);
    }
    NVIC_ClearPendingIRQ(SAADC_IRQn);
}

Best,

Taylor

RE: SAADC will not start

hmolesworth — Tue, 07 Jan 2025 22:34:08 GMT

Bug here:

    ADC->INTENSET = SAADC_INTENSET_END_Set;

Fix:

    ADC->INTENSET = SAADC_INTENSET_END_Set << SAADC_INTENSET_END_Pos;

Some stuff like events are in bit 0, other stuff ain't ..