2.8.3.1.2 Code

Add to the main application source file, outside of any functions:

struct dac_module dac_instance;

struct adc_module adc_instance;

struct dma_resource example_resource;

COMPILER_ALIGNED(16)
DmacDescriptor example_descriptor SECTION_DMAC_DESCRIPTOR;

Copy-paste the following setup code to your user application:

void configure_adc(void)
{
    struct adc_config config_adc;

    adc_get_config_defaults(&config_adc);

#if !(SAML21)
#if !(SAMC21)
    config_adc.gain_factor     = ADC_GAIN_FACTOR_DIV2;
#endif
    config_adc.resolution      = ADC_RESOLUTION_10BIT;
#endif
    config_adc.clock_prescaler = ADC_CLOCK_PRESCALER_DIV16;
    config_adc.reference       = ADC_REFERENCE_INTVCC1;
    config_adc.positive_input  = ADC_POSITIVE_INPUT_PIN4;
    config_adc.freerunning     = true;
    config_adc.left_adjust     = false;

#if (SAMC21)
    adc_init(&adc_instance, ADC1, &config_adc);
#else
    adc_init(&adc_instance, ADC, &config_adc);
#endif

    adc_enable(&adc_instance);
}

void configure_dac(void)
{
    struct dac_config config_dac;

    dac_get_config_defaults(&config_dac);

#if (SAML21)
    config_dac.reference = DAC_REFERENCE_INTREF;
#else
    config_dac.reference = DAC_REFERENCE_AVCC;
#endif

    dac_init(&dac_instance, DAC, &config_dac);

}

void configure_dac_channel(void)
{
    struct dac_chan_config config_dac_chan;

    dac_chan_get_config_defaults(&config_dac_chan);

    dac_chan_set_config(&dac_instance, DAC_CHANNEL_0, &config_dac_chan);

    dac_chan_enable(&dac_instance, DAC_CHANNEL_0);
}

void configure_dma_resource(struct dma_resource *resource)
{
    struct dma_resource_config config;

    dma_get_config_defaults(&config);

#if (SAMC21)
    config.peripheral_trigger = ADC1_DMAC_ID_RESRDY;
#else
    config.peripheral_trigger = ADC_DMAC_ID_RESRDY;
#endif
    config.trigger_action = DMA_TRIGGER_ACTON_BEAT;

    dma_allocate(resource, &config);
}

void setup_transfer_descriptor(DmacDescriptor *descriptor)
{
    struct dma_descriptor_config descriptor_config;

    dma_descriptor_get_config_defaults(&descriptor_config);

    descriptor_config.beat_size = DMA_BEAT_SIZE_HWORD;
    descriptor_config.dst_increment_enable = false;
    descriptor_config.src_increment_enable = false;
    descriptor_config.block_transfer_count = 1000;
    descriptor_config.source_address = (uint32_t)(&adc_instance.hw->RESULT.reg);
#if (SAML21)
    descriptor_config.destination_address = (uint32_t)(&dac_instance.hw->DATA[DAC_CHANNEL_0].reg);
#else
    descriptor_config.destination_address = (uint32_t)(&dac_instance.hw->DATA.reg);
#endif
    descriptor_config.next_descriptor_address = (uint32_t)descriptor;

    dma_descriptor_create(descriptor, &descriptor_config);
}

Add to user application initialization (typically the start of main()):

configure_adc();

configure_dac();

configure_dac_channel();

dac_enable(&dac_instance);

configure_dma_resource(&example_resource);

setup_transfer_descriptor(&example_descriptor);

dma_add_descriptor(&example_resource, &example_descriptor);