SAML21走起13:ADC DMA DAC

#include <asf.h>



/* AC module software instance (must not go out of scope while in use) */

struct dac_module dac_instance;

struct adc_module adc_instance;

struct dma_resource example_resource;

COMPILER_ALIGNED(16)

DmacDescriptor example_descriptor SECTION_DMAC_DESCRIPTOR;



void configure_adc(void);

void configure_dac(void);

void configure_dac_channel(void);

void configure_dma_resource(struct dma_resource *resource);

void setup_transfer_descriptor(DmacDescriptor *descriptor);









void configure_adc(void)

{

        struct adc_config config_adc;

        adc_get_config_defaults(&config_adc);

        #if !(SAML21)

        config_adc.gain_factor     = ADC_GAIN_FACTOR_DIV2;

        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;

        adc_init(&adc_instance, ADC, &config_adc);

        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);

        config.peripheral_trigger = ADC_DMAC_ID_RESRDY;

        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);

}









int main (void)

{

        system_init();

         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);

        

         adc_start_conversion(&adc_instance);

         dma_start_transfer_job(&example_resource);

         while (true) {

         }

        

}