AT32 ADC

AT32 ADC — 三 ADC 同步触发

AT32 AT32F403A_407_Firmware_Library V2.2.2 ADC 三 ADC 同步触发 示例教学

ADC — 三 ADC 同步触发

固件库: AT32F403A_407_Firmware_Library V2.2.2
芯片: AT32
源文件: AT32/AT32F403A_407_Firmware_Library_V2.2.2/project/at_start_f403a/examples/adc/triple_adc_synchro_trigger/src/main.c

功能简介

本示例演示多 ADC 协同工作。多个 ADC 同时采样不同通道，适用于需要同步采集多路信号的场景（如三相电压/电流）。

硬件准备

  • 电位器（可调电阻）连接到 ADC 输入引脚
  • 或使用内部温度传感器（无需额外硬件）

完整代码 

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#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
__IO uint32_t adc1_ordinary_valuetab[3];
__IO uint16_t adc3_ordinary_valuetab[3];
__IO uint32_t dma1_trans_complete_flag = 0;
__IO uint16_t adc12_ordinary_conversion_times_index = 0;
__IO uint32_t dma2_trans_complete_flag = 0;
__IO uint16_t adc3_ordinary_conversion_times_index = 0;

static void gpio_config(void)
{
  gpio_init_type gpio_initstructure;
  crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_GPIOC_PERIPH_CLOCK, TRUE);

  gpio_default_para_init(&gpio_initstructure);
  gpio_initstructure.gpio_mode = GPIO_MODE_ANALOG;
  gpio_initstructure.gpio_pins = GPIO_PINS_4 | GPIO_PINS_5 | GPIO_PINS_6 | GPIO_PINS_7;
  gpio_init(GPIOA, &gpio_initstructure);

  gpio_initstructure.gpio_mode = GPIO_MODE_ANALOG;
  gpio_initstructure.gpio_pins = GPIO_PINS_0 | GPIO_PINS_1;
  gpio_init(GPIOB, &gpio_initstructure);

  gpio_initstructure.gpio_mode = GPIO_MODE_ANALOG;
  gpio_initstructure.gpio_pins = GPIO_PINS_0 | GPIO_PINS_1 | GPIO_PINS_2;
  gpio_init(GPIOC, &gpio_initstructure);
}

static void dma_config(void)
{
  dma_init_type dma_init_struct;
  crm_periph_clock_enable(CRM_DMA1_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_DMA2_PERIPH_CLOCK, TRUE);
  nvic_irq_enable(DMA1_Channel1_IRQn, 0, 0);
  nvic_irq_enable(DMA2_Channel4_5_IRQn, 0, 0);
  dma_reset(DMA1_CHANNEL1);
  dma_reset(DMA2_CHANNEL5);
  dma_default_para_init(&dma_init_struct);
  dma_init_struct.buffer_size = 3;
  dma_init_struct.direction = DMA_DIR_PERIPHERAL_TO_MEMORY;
  dma_init_struct.memory_base_addr = (uint32_t)adc1_ordinary_valuetab;
  dma_init_struct.memory_data_width = DMA_MEMORY_DATA_WIDTH_WORD;
  dma_init_struct.memory_inc_enable = TRUE;
  dma_init_struct.peripheral_base_addr = (uint32_t)&(ADC1->odt);
  dma_init_struct.peripheral_data_width = DMA_PERIPHERAL_DATA_WIDTH_WORD;
  dma_init_struct.peripheral_inc_enable = FALSE;
  dma_init_struct.priority = DMA_PRIORITY_HIGH;
  dma_init_struct.loop_mode_enable = TRUE;
  dma_init(DMA1_CHANNEL1, &dma_init_struct);

  dma_init_struct.memory_base_addr = (uint32_t)adc3_ordinary_valuetab;
  dma_init_struct.memory_data_width = DMA_MEMORY_DATA_WIDTH_HALFWORD;
  dma_init_struct.peripheral_base_addr = (uint32_t)&(ADC3->odt);
  dma_init_struct.peripheral_data_width = DMA_PERIPHERAL_DATA_WIDTH_HALFWORD;
  dma_init(DMA2_CHANNEL5, &dma_init_struct);

  dma_interrupt_enable(DMA1_CHANNEL1, DMA_FDT_INT, TRUE);
  dma_interrupt_enable(DMA2_CHANNEL5, DMA_FDT_INT, TRUE);
}

static void tmr1_config(void)
{
  crm_clocks_freq_type crm_clocks_freq_struct = {0};

  /* get system clock */
  crm_clocks_freq_get(&crm_clocks_freq_struct);

  crm_periph_clock_enable(CRM_TMR1_PERIPH_CLOCK, TRUE);

  /* (systemclock/(systemclock/10000))/10000 = 1Hz(1s) */
  tmr_base_init(TMR1, 9999, (crm_clocks_freq_struct.sclk_freq/10000 - 1));
  tmr_cnt_dir_set(TMR1, TMR_COUNT_UP);
  tmr_clock_source_div_set(TMR1, TMR_CLOCK_DIV1);
  tmr_primary_mode_select(TMR1, TMR_PRIMARY_SEL_OVERFLOW);
}

static void adc_config(void)
{
  adc_base_config_type adc_base_struct;
  crm_periph_clock_enable(CRM_ADC1_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_ADC2_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_ADC3_PERIPH_CLOCK, TRUE);
  adc_reset(ADC1);
  adc_reset(ADC2);
  adc_reset(ADC3);
  crm_adc_clock_div_set(CRM_ADC_DIV_4);
  adc_base_default_para_init(&adc_base_struct);

  /* select combine mode */
  adc_combine_mode_select(ADC_ORDINARY_SMLT_ONLY_MODE);

  /* ADC1 config */
  adc_base_struct.sequence_mode = TRUE;
  adc_base_struct.repeat_mode = FALSE;
  adc_base_struct.data_align = ADC_RIGHT_ALIGNMENT;
  adc_base_struct.ordinary_channel_length = 3;
  adc_base_config(ADC1, &adc_base_struct);
  adc_ordinary_channel_set(ADC1, ADC_CHANNEL_4, 1, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC1, ADC_CHANNEL_5, 2, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC1, ADC_CHANNEL_6, 3, ADC_SAMPLETIME_239_5);
  adc_ordinary_conversion_trigger_set(ADC1, ADC12_ORDINARY_TRIG_TMR1TRGOUT, TRUE);
  adc_dma_mode_enable(ADC1, TRUE);

  /* ADC2 config */
  adc_base_config(ADC2, &adc_base_struct);
  adc_ordinary_channel_set(ADC2, ADC_CHANNEL_7, 1, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC2, ADC_CHANNEL_8, 2, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC2, ADC_CHANNEL_9, 3, ADC_SAMPLETIME_239_5);
  adc_ordinary_conversion_trigger_set(ADC2, ADC12_ORDINARY_TRIG_SOFTWARE, TRUE);

  /* ADC3 config */
  adc_base_config(ADC3, &adc_base_struct);
  adc_ordinary_channel_set(ADC3, ADC_CHANNEL_10, 1, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC3, ADC_CHANNEL_11, 2, ADC_SAMPLETIME_239_5);
  adc_ordinary_channel_set(ADC3, ADC_CHANNEL_12, 3, ADC_SAMPLETIME_239_5);
  adc_ordinary_conversion_trigger_set(ADC3, ADC3_ORDINARY_TRIG_TMR1TRGOUT, TRUE);
  adc_dma_mode_enable(ADC3, TRUE);

  adc_enable(ADC1, TRUE);
  adc_enable(ADC2, TRUE);

  /* ADC calibration */
  adc_calibration_init(ADC1);
  while(adc_calibration_init_status_get(ADC1));
  adc_calibration_start(ADC1);
  while(adc_calibration_status_get(ADC1));
  adc_calibration_init(ADC2);
  while(adc_calibration_init_status_get(ADC2));
  adc_calibration_start(ADC2);
  while(adc_calibration_status_get(ADC2));

  adc_enable(ADC3, TRUE);
  adc_calibration_init(ADC3);
  while(adc_calibration_init_status_get(ADC3));
  adc_calibration_start(ADC3);
  while(adc_calibration_status_get(ADC3));
}

int main(void)
{
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);
  system_clock_config();
  at32_board_init();
  at32_led_off(LED2);
  at32_led_off(LED3);
  at32_led_off(LED4);
  uart_print_init(115200);
  gpio_config();
  tmr1_config();
  dma_config();
  adc_config();

  /* enable DMA after ADC activation */
  dma_channel_enable(DMA1_CHANNEL1, TRUE);
  dma_channel_enable(DMA2_CHANNEL5, TRUE);

  printf("triple_adc_synchro_trigger \r\n");

  tmr_counter_enable(TMR1, TRUE);
  while(1)
  {
    /* wait ordinary conversion end */
    if(adc12_ordinary_conversion_times_index != dma1_trans_complete_flag)
    {
      adc12_ordinary_conversion_times_index = dma1_trans_complete_flag;
      printf("adc12_ordinary_conversion_times_index = %d\r\n",adc12_ordinary_conversion_times_index);
      printf("adc1_ordinary_valuetab[0] = 0x%x\r\n", adc1_ordinary_valuetab[0]);
      printf("adc1_ordinary_valuetab[1] = 0x%x\r\n", adc1_ordinary_valuetab[1]);
      printf("adc1_ordinary_valuetab[2] = 0x%x\r\n", adc1_ordinary_valuetab[2]);
      printf("\r\n");
      at32_led_toggle(LED2);
    }

    /* wait preempt conversion end */
    if(adc3_ordinary_conversion_times_index != dma2_trans_complete_flag)
    {
      adc3_ordinary_conversion_times_index = dma2_trans_complete_flag;
      printf("adc3_ordinary_conversion_times_index = %d\r\n",adc3_ordinary_conversion_times_index);
      printf("adc3_ordinary_valuetab[0] = 0x%x\r\n", adc3_ordinary_valuetab[0]);
      printf("adc3_ordinary_valuetab[1] = 0x%x\r\n", adc3_ordinary_valuetab[1]);
      printf("adc3_ordinary_valuetab[2] = 0x%x\r\n", adc3_ordinary_valuetab[2]);
      printf("\r\n");
      at32_led_toggle(LED3);
    }
  }
}

代码讲解

系统时钟初始化：配置 MCU 的主频和时钟树。不同芯片的时钟配置不同，一般由工具生成。

板级初始化：初始化开发板上的 LED、按键等基础外设。

串口初始化：配置串口波特率（这里是 115200），使能 printf 重定向。

printf 输出：通过串口打印调试信息。需要先调用 uart_print_init 完成重定向。

GPIO 配置：设置引脚为输出/输入模式，选择推挽/开漏输出，配置上拉/下拉。

ADC 配置：选择采样通道、采样时间、触发方式、数据对齐方式。采样时间越长精度越高。

DMA 配置：设置源地址、目标地址、传输方向、数据宽度。DMA 搬运数据不占用 CPU。

定时器配置：设置预分频器（PSC）和重装载值（ARR），定时时间 = (PSC+1) × (ARR+1) / 时钟频率。

中断优先级配置：NVIC 设置中断的抢占优先级和子优先级。数字越小优先级越高。

校准：ADC 使用前必须校准，消除工艺偏差。校准期间不要操作 ADC。

实验现象

  • 串口助手打印 ADC 采样值
  • 转动电位器时数值变化
  • 温度传感器示例会显示芯片温度

注意事项

  • ADC 参考电压影响测量精度
  • 采样时间要根据信号源阻抗选择
  • 使用前务必校准（Calibration）
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