bms/Application/bsp/gd32_adc.c

#include "gd32_adc.h"
#include "gpio.h"
#include "clock.h"
/* For 12-bits resolution, the total conversion time is 
 *sampling time + 12.5 ADCCLK cycles 
 *all channel is enabled oversample to reach 16bit accurate
*/
static int volatile adc_work = ADC_WORK_IDLE;
//#define DMA_ADC_CH DMA_CH0
#ifdef DMA_ADC_CH
#define dma_irq					DMA_Channel0_IRQn
#define dma_buf_len 66
static uint16_t dma_buf[dma_buf_len]; 
#endif
void adc_init(void){
	rcu_periph_clock_enable(RCU_GPIOA);
	rcu_periph_clock_enable(RCU_GPIOB);	
	gpio_mode_analog_input(GPIOA, GPIO_PIN_1|GPIO_PIN_4|GPIO_PIN_5|GPIO_PIN_6|GPIO_PIN_7);
	gpio_mode_analog_input(GPIOB, GPIO_PIN_1|GPIO_PIN_0);

    /* config ADC clock */
    rcu_adc_clock_config(RCU_ADCCK_APB2_DIV6); //adc clock:28M 

	rcu_periph_clock_enable(RCU_ADC);
	adc_deinit();
    /* ADC trigger config */
    adc_external_trigger_source_config(ADC_REGULAR_CHANNEL, ADC_EXTTRIG_REGULAR_NONE);
	/* ADC data alignment config */
	adc_data_alignment_config(ADC_DATAALIGN_RIGHT);
	/* ADC channel length config */
	adc_channel_length_config(ADC_REGULAR_CHANNEL, 1);

	adc_resolution_config(ADC_RESOLUTION_12B);
 
	//adc_special_function_config(ADC_SCAN_MODE,ENABLE);

	adc_discontinuous_mode_config(ADC_REGULAR_CHANNEL, 1);

	adc_external_trigger_config(ADC_REGULAR_CHANNEL, ENABLE);

}

#ifdef DMA_ADC_CH
void dma_config(void)
{
    /* ADC_DMA_channel configuration */
    dma_parameter_struct dma_data_parameter;
    
    /* ADC DMA_channel configuration */
    dma_deinit(DMA_ADC_CH);
    
    /* initialize DMA single data mode */
    dma_data_parameter.periph_addr  = (uint32_t)(&ADC_RDATA);
    dma_data_parameter.periph_inc   = DMA_PERIPH_INCREASE_DISABLE;
    dma_data_parameter.memory_addr  = (uint32_t)dma_buf;
    dma_data_parameter.memory_inc   = DMA_MEMORY_INCREASE_DISABLE;
    dma_data_parameter.periph_width = DMA_PERIPHERAL_WIDTH_16BIT;
    dma_data_parameter.memory_width = DMA_MEMORY_WIDTH_16BIT;  
    dma_data_parameter.direction    = DMA_PERIPHERAL_TO_MEMORY;
    dma_data_parameter.number       = 1U;
    dma_data_parameter.priority     = DMA_PRIORITY_HIGH;
    dma_init(DMA_ADC_CH, &dma_data_parameter);

    dma_circulation_disable(DMA_ADC_CH);

	dma_interrupt_enable(DMA_ADC_CH, DMA_INT_FTF);
	
	nvic_priority_group_set(NVIC_PRIGROUP_PRE4_SUB0);
	nvic_irq_enable(dma_irq, 4U, 0U);

}

/* step 1 */
int adc_start_sample(int chan){
	//hardware oversample to 16bit
	adc_oversample_mode_config(ADC_OVERSAMPLING_ALL_CONVERT, ADC_OVERSAMPLING_SHIFT_4B, ADC_OVERSAMPLING_RATIO_MUL256);
	adc_oversample_mode_enable();
    /* use max convert time to make sure the adc work fine */
    adc_regular_channel_config(0, chan, ADC_SAMPLETIME_55POINT5);//239.5 + 12.5 = 242 cycle, 242/(28*1000000)
	adc_enable();
	adc_work = ADC_WORK_ING;
}
/* step 2 */
int adc_start_calibration(void){
	/* ADC calibration and reset calibration */
	adc_calibration_enable();
}
int adc_sample_avg(int chan, int times){
    /* configure the number of remaining data to be transferred */
    DMA_CHCNT(DMA_ADC_CH) = (times & DMA_CHANNEL_CNT_MASK);	
	dma_channel_enable(DMA_ADC_CH);
	/* ADC DMA function enable */
    adc_dma_mode_enable();
    /* ADC software trigger enable */
    adc_software_trigger_enable(ADC_REGULAR_CHANNEL);
}

void DMA_Channel0_IRQHandler(void){
	adc_disable();
	dma_interrupt_flag_clear(DMA_ADC_CH, DMA_INT_FLAG_FTF);
	dma_channel_disable(DMA_ADC_CH);
}

int adc_get_sample(void){
	if (adc_work != ADC_WORK_FINISH){
		return 0x7FFFFFFF;
	}
	int value = 0;
	int count = DMA_CHCNT(DMA_ADC_CH) & DMA_CHANNEL_CNT_MASK;	
	int min = 0xFFFFF;
	int max = -0xFFFFF;
	int i;
	for (i = 0; i < count; i++){
		int one = dma_buf[i];
		value += one;
		if (one > max){
			max = one;
		}
		if (one < min) {
			min = one;
		}
	}
	adc_work = ADC_WORK_FINISH;
	return (value - min - max)/(count - 2);
}

#else

int adc_sample(int chan, int calibration){
	int value = -0xFFFFFF;
	int mask = 0xFFFF;
	//hardware oversample to 16bit
	adc_oversample_mode_config(ADC_OVERSAMPLING_ALL_CONVERT, ADC_OVERSAMPLING_SHIFT_4B, ADC_OVERSAMPLING_RATIO_MUL256);
	adc_oversample_mode_enable();

    /* use max convert time to make sure the adc work fine */
    adc_regular_channel_config(0, chan, ADC_SAMPLETIME_55POINT5);//239.5 + 12.5 = 242 cycle, 242/(28*1000000)
	adc_enable();
	delay_us(1000); //MUST delay, for adc work fine
	if (calibration) {
		/* ADC calibration and reset calibration */
    	adc_calibration_enable();
	}
	
	adc_software_trigger_enable(ADC_REGULAR_CHANNEL);
    while(SET != adc_flag_get(ADC_FLAG_EOC));
    value = adc_regular_data_read();
	adc_flag_clear(ADC_FLAG_EOC);
	adc_disable();

	return value & mask;
}

int adc_sample_avg(int chan, int times){
	int value = 0;
	int count = 0;
	int min = 0xFFFFF;
	int max = -0xFFFFF;
	//hardware oversample to 16bit
	adc_oversample_mode_config(ADC_OVERSAMPLING_ALL_CONVERT, ADC_OVERSAMPLING_SHIFT_4B, ADC_OVERSAMPLING_RATIO_MUL256);
	adc_oversample_mode_enable();
    /* use max convert time to make sure the adc work fine */
    adc_regular_channel_config(0, chan, ADC_SAMPLETIME_55POINT5);//239.5 + 12.5 = 242 cycle, 242/(28*1000000)
	adc_enable();
	delay_us(1000); //MUST delay, for adc work fine
	/* ADC calibration and reset calibration */
	adc_calibration_enable();

	while(count < times){
		adc_software_trigger_enable(ADC_REGULAR_CHANNEL);
    	while(SET != adc_flag_get(ADC_FLAG_EOC));
    	int one = adc_regular_data_read();
		adc_flag_clear(ADC_FLAG_EOC);		
		value += (one & 0xFFFF);
		count ++;
		if (one > max){
			max = one;
		}
		if (one < min) {
			min = one;
		}
	}
	adc_disable();
	return (value - min - max)/(times-2);
}
#endif /* DMA_ADC_CH */