AT32 ACC — calibration

Tue, 08 Sep 2026 14:52:21 +0800

ACC — calibration

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/acc/calibration/src/main.c

功能简介

本示例演示自动比较器校准 (ACC) 的基本用法。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "cdc_class.h"
#include "cdc_desc.h"
#include "usbd_int.h"

void clkout_config(void)
{
  gpio_init_type gpio_init_struct;

  /* enable gpio port clock */
  crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);

  /* set default parameter */
  gpio_default_para_init(&gpio_init_struct);

  /* clkout gpio init */
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
  gpio_init_struct.gpio_pins = GPIO_PINS_8;
  gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
  gpio_init(GPIOA, &gpio_init_struct);

  /* config clkout division */
  crm_clkout_div_set(CRM_CLKOUT_DIV_1);

  /* config clkout clock */
  crm_clock_out_set(CRM_CLKOUT_USB);
}

int main(void)
{
  uint16_t data_len;

  uint32_t timeout;

  uint8_t send_zero_packet = 0;

  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  /* sclk = 240mhz from hick */
  system_clock_config_for_acc();

  at32_board_init();

  usb_clock48m_select(USB_CLK_HICK);

  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 1, 0);

  usbd_core_init(&usb_core_dev, USB, &cdc_class_handler, &cdc_desc_handler, 0);

  usbd_connect(&usb_core_dev);

  /* acc config */
  crm_periph_clock_enable(CRM_ACC_PERIPH_CLOCK, TRUE);

  /* enable the acc calibration ready interrupt */
  acc_interrupt_enable(ACC_CALRDYIEN_INT, TRUE);

  /* enable the acc reference signal lost interrupt */
  acc_interrupt_enable(ACC_EIEN_INT, TRUE);

  /* config nvic for acc int  */
  nvic_irq_enable(ACC_IRQn, 2, 0);

  /* update the c1\c2\c3 value */
  acc_c2_value = 8000;
  #ifdef ACC_CAL
  acc_write_c1(acc_c2_value - 20);
  acc_write_c2(acc_c2_value);
  acc_write_c3(acc_c2_value + 20);
  #else
  acc_write_c1(acc_c2_value - 10);
  acc_write_c2(acc_c2_value);
  acc_write_c3(acc_c2_value + 10);
  #endif

  /* open acc calibration */
  #if defined(ACC_CAL)
    acc_calibration_mode_enable(ACC_CAL_HICKCAL, TRUE);
  #elif defined(ACC_TRIM)
    acc_calibration_mode_enable(ACC_CAL_HICKTRIM, TRUE);
  #endif

  while(1)
  {
    /* get usb vcp receive data */
    data_len = usb_vcp_get_rxdata(&usb_core_dev, usb_buffer);

    if(data_len > 0 || send_zero_packet == 1)
    {

      /* bulk transfer is complete when the endpoint does one of the following
         1 has transferred exactly the amount of data expected
         2 transfers a packet with a payload size less than wMaxPacketSize or transfers a zero-length packet
      */
      if(data_len > 0)
        send_zero_packet = 1;

      if(data_len == 0)
        send_zero_packet = 0;

      timeout = 5000000;
      do
      {
        /* send data to host */
        if(usb_vcp_send_data(&usb_core_dev, usb_buffer, data_len) == SUCCESS)
        {
          break;
        }
      }while(timeout --);
    }
  }
}

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。

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。

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。

Calibration on CLing

AT32 ACC — calibration

ACC — calibration

功能简介

完整代码

代码讲解