用SAM-BA或JLINK跑ATSAM4E16的程序(24)AFEC自动比较

#include <stdio.h>

#include <string.h>

#include <assert.h>

#include "asf.h"



/** Reference voltage for AFEC in mv. */

#define VOLT_REF        (3300)



/** The maximal digital value */

#define MAX_DIGITAL     (4095UL)



#define STRING_EOL    "\r"

#define STRING_HEADER "-- AFEC Automatic Comparison Example --\r\n" \

                "-- "BOARD_NAME" --\r\n" \

                "-- Compiled: "__DATE__" "__TIME__" --"STRING_EOL



/** Low threshold */

static uint16_t gs_us_low_threshold = 0;

/** High threshold */

static uint16_t gs_us_high_threshold = 0;



/**

 * \brief Configure UART console.

 */

static void configure_console(void)

{

        const usart_serial_options_t uart_serial_options = {

                .baudrate = CONF_UART_BAUDRATE,

        #ifdef CONF_UART_CHAR_LENGTH

                .charlength = CONF_UART_CHAR_LENGTH,

        #endif

                .paritytype = CONF_UART_PARITY,

        #ifdef CONF_UART_STOP_BITS

                .stopbits = CONF_UART_STOP_BITS,

        #endif

        };



        /* Configure console UART. */

        sysclk_enable_peripheral_clock(CONSOLE_UART_ID);

        stdio_serial_init(CONF_UART, &uart_serial_options);

}



/**

 * \brief Callback function for AFEC enter compasion window interrupt.

 */

static void afec_print_comp_result(void)

{

        uint16_t us_adc;



        /* Disable Compare Interrupt. */

        afec_disable_interrupt(AFEC0, AFEC_INTERRUPT_COMP_ERROR);

        

        us_adc = afec_channel_get_value(AFEC0, AFEC_CHANNEL_POTENTIOMETER);



        printf("-ISR-:Potentiometer voltage %d mv is in the comparison "

                        "window:%d -%d mv!\n\r",

                        (int)(us_adc * VOLT_REF / MAX_DIGITAL),

                        (int)(gs_us_low_threshold * VOLT_REF / MAX_DIGITAL),

                        (int)(gs_us_high_threshold * VOLT_REF / MAX_DIGITAL));

}



/**

 * \brief Application entry point.

 *

 * \return Unused (ANSI-C compatibility).

 */

int main(void)

{

        /* Initialize the SAM system. */

        sysclk_init();

        board_init();



        configure_console();



        /* Output example information. */

        puts(STRING_HEADER);



        gs_us_low_threshold = 0x0;

        gs_us_high_threshold = 0x7FF;



        afec_enable(AFEC0);



        struct afec_config afec_cfg;



        afec_get_config_defaults(&afec_cfg);

        afec_init(AFEC0, &afec_cfg);



        struct afec_ch_config afec_ch_cfg;

        afec_ch_get_config_defaults(&afec_ch_cfg);

        

#if (SAMV71 || SAMV70 || SAME70 || SAMS70) 

        /*

         * Because the internal AFEC offset is 0x200, it should cancel it and shift

         * down to 0.

         */

        afec_channel_set_analog_offset(AFEC0, AFEC_CHANNEL_POTENTIOMETER, 0x200);



        afec_ch_cfg.gain = AFEC_GAINVALUE_0;



#else

        /*

         * Because the internal AFEC offset is 0x800, it should cancel it and shift

         * down to 0.

         */

        afec_channel_set_analog_offset(AFEC0, AFEC_CHANNEL_POTENTIOMETER, 0x800);

#endif



        afec_ch_set_config(AFEC0, AFEC_CHANNEL_POTENTIOMETER, &afec_ch_cfg);

        afec_set_trigger(AFEC0, AFEC_TRIG_SW);



        afec_set_comparison_mode(AFEC0, AFEC_CMP_MODE_2, AFEC_CHANNEL_POTENTIOMETER, 0);

        afec_set_comparison_window(AFEC0, gs_us_low_threshold, gs_us_high_threshold);



        /* Enable channel for potentiometer. */

        afec_channel_enable(AFEC0, AFEC_CHANNEL_POTENTIOMETER);





        afec_set_callback(AFEC0, AFEC_INTERRUPT_COMP_ERROR, afec_print_comp_result, 1);



        while (1) {

                afec_start_software_conversion(AFEC0);

                delay_ms(1000);



        }

}