SAM4S2A ADC

ASF Wizard

• ADC - Analog-to-digital Converter (driver): The Analog to Digital Converter is able to capture analog signals and transform them into digital format with 10-bit or 12-bit resolution.

Enum

/* The max ADC clock freq definition*/
#define ADC_FREQ_MAX 20000000
/* The min ADC clock freq definition*/
#define ADC_FREQ_MIN 1000000
/* The normal ADC startup time*/
#define ADC_STARTUP_NORM 40
/* The fast ADC startup time*/
#define ADC_STARTUP_FAST 12

/* Definitions for ADC resolution */
enum adc_resolution_t {
    ADC_10_BITS = ADC_MR_LOWRES_BITS_10, /* ADC 10-bit resolution */
    ADC_12_BITS = ADC_MR_LOWRES_BITS_12  /* ADC 12-bit resolution */
};

/* Definitions for ADC trigger */
enum adc_trigger_t {
    /* Starting a conversion is only possible by software. */
    ADC_TRIG_SW = ADC_MR_TRGEN_DIS,
    /* External trigger */
    ADC_TRIG_EXT = ADC_MR_TRGSEL_ADC_TRIG0 | ADC_MR_TRGEN,
    /* TIO Output of the Timer Counter Channel 0 */
    ADC_TRIG_TIO_CH_0 = ADC_MR_TRGSEL_ADC_TRIG1 | ADC_MR_TRGEN,
    /* TIO Output of the Timer Counter Channel 1 */
    ADC_TRIG_TIO_CH_1 = ADC_MR_TRGSEL_ADC_TRIG2 | ADC_MR_TRGEN,
    /* TIO Output of the Timer Counter Channel 2 */
    ADC_TRIG_TIO_CH_2 = ADC_MR_TRGSEL_ADC_TRIG3 | ADC_MR_TRGEN,
    /* PWM Event Line 0 */
    ADC_TRIG_PWM_EVENT_LINE_0 = ADC_MR_TRGSEL_ADC_TRIG4 | ADC_MR_TRGEN,
    /* PWM Event Line 1 */
    ADC_TRIG_PWM_EVENT_LINE_1 = ADC_MR_TRGSEL_ADC_TRIG5 | ADC_MR_TRGEN
};

/* Definitions for ADC channel number */
enum adc_channel_num_t {
    ADC_CHANNEL_0          = 0,
    ADC_CHANNEL_1          = 1,
    ADC_CHANNEL_2          = 2,
    ADC_CHANNEL_3          = 3,
    ADC_CHANNEL_4          = 4,
    ADC_CHANNEL_5          = 5,
    ADC_CHANNEL_6          = 6,
    ADC_CHANNEL_7          = 7,
    ADC_CHANNEL_8          = 8,
    ADC_CHANNEL_9          = 9,
    ADC_CHANNEL_10         = 10,
    ADC_CHANNEL_11         = 11,
    ADC_CHANNEL_12         = 12,
    ADC_CHANNEL_13         = 13,
    ADC_CHANNEL_14         = 14,
    ADC_TEMPERATURE_SENSOR = 15,
};

/* Definitions for ADC gain value */
enum adc_gainvalue_t {
    ADC_GAINVALUE_0 = 0,
    ADC_GAINVALUE_1 = 1,
    ADC_GAINVALUE_2 = 2,
    ADC_GAINVALUE_3 = 3
};

/* Definitions for ADC analog settling time */
enum adc_settling_time_t {
    ADC_SETTLING_TIME_0 = ADC_MR_SETTLING_AST3,
    ADC_SETTLING_TIME_1 = ADC_MR_SETTLING_AST5,
    ADC_SETTLING_TIME_2 = ADC_MR_SETTLING_AST9,
    ADC_SETTLING_TIME_3 = ADC_MR_SETTLING_AST17
};

/** Definitions for ADC Start Up Time */
enum adc_startup_time {
    ADC_STARTUP_TIME_0  = ADC_MR_STARTUP_SUT0,
    ADC_STARTUP_TIME_1  = ADC_MR_STARTUP_SUT8,
    ADC_STARTUP_TIME_2  = ADC_MR_STARTUP_SUT16,
    ADC_STARTUP_TIME_3  = ADC_MR_STARTUP_SUT24,
    ADC_STARTUP_TIME_4  = ADC_MR_STARTUP_SUT64,
    ADC_STARTUP_TIME_5  = ADC_MR_STARTUP_SUT80,
    ADC_STARTUP_TIME_6  = ADC_MR_STARTUP_SUT96,
    ADC_STARTUP_TIME_7  = ADC_MR_STARTUP_SUT112,
    ADC_STARTUP_TIME_8  = ADC_MR_STARTUP_SUT512,
    ADC_STARTUP_TIME_9  = ADC_MR_STARTUP_SUT576,
    ADC_STARTUP_TIME_10 = ADC_MR_STARTUP_SUT640,
    ADC_STARTUP_TIME_11 = ADC_MR_STARTUP_SUT704,
    ADC_STARTUP_TIME_12 = ADC_MR_STARTUP_SUT768,
    ADC_STARTUP_TIME_13 = ADC_MR_STARTUP_SUT832,
    ADC_STARTUP_TIME_14 = ADC_MR_STARTUP_SUT896,
    ADC_STARTUP_TIME_15 = ADC_MR_STARTUP_SUT960
};

Examples

#include "conf_uart_serial.h"

#include <asf.h>

void serial_init(void) {
    pio_configure(
        PINS_USART0_PIO, PINS_USART0_TYPE, PINS_USART0_MASK, PINS_USART0_ATTR);
    pmc_enable_periph_clk(USART_SERIAL_ID);
    sysclk_enable_peripheral_clock(USART_SERIAL_ID);

    const usart_serial_options_t usart_serial_options
        = {.baudrate   = USART_SERIAL_BAUDRATE,
           .charlength = USART_SERIAL_CHAR_LENGTH,
           .paritytype = USART_SERIAL_PARITY,
           .stopbits   = USART_SERIAL_STOP_BIT};

    stdio_serial_init(USART_SERIAL, &usart_serial_options);
}

void adc_setup(void) {
    pmc_enable_periph_clk(ID_ADC);

    adc_init(ADC, F_CPU, 6400000, ADC_STARTUP_TIME_8);
    adc_configure_timing(ADC, 0, ADC_SETTLING_TIME_3, 1);
    adc_set_resolution(ADC, ADC_MR_LOWRES_BITS_10);
    // print
    adc_check(ADC, F_CPU);

    adc_disable_all_channel(ADC);
    adc_enable_channel(ADC, ADC_CHANNEL_0);
    adc_enable_channel(ADC, ADC_CHANNEL_2);

    adc_configure_trigger(ADC, ADC_TRIG_SW, 0);

    adc_start(ADC);
}

int main(void) {
    sysclk_init();
    board_init();
    /* Insert application code here, after the board has been initialized. */
    wdt_disable(WDT);

    serial_init();

    adc_setup();

    for(;;) {
        if(adc_get_channel_status(ADC, ADC_CHANNEL_0)
           && adc_get_channel_status(ADC, ADC_CHANNEL_2)) {
            printf("%d,%d\n",
                   adc_get_channel_value(ADC, ADC_CHANNEL_0),
                   adc_get_channel_value(ADC, ADC_CHANNEL_2));
            adc_start(ADC);
        }
    }
}