USB_DEVICE on CLing

AT32 — USB 设备

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

AT32 — USB 设备

固件库: AT32F403A_407_Firmware_Library V2.2.2
示例数: 13

什么是 USB 设备?

USB 设备模式让 MCU 模拟各种 USB 设备（键盘、鼠标、虚拟串口、U 盘等），即插即用。

示例列表

USB 音频 — audio
复合设备: 音频 + HID — composite_audio_hid
复合设备: VCP + 键盘 — composite_vcp_keyboard
复合设备: VCP + MSC — composite_vcp_msc
自定义 HID — custom_hid
USB 键盘 — keyboard
USB 鼠标 — mouse
USB 大容量存储 — msc
USB 打印机 — printer
虚拟串口回环 — vcp_loopback
虚拟串口 (VCP) — virtual_comport
虚拟 MSC + IAP — virtual_msc_iap
WinUSB — winusb

AT32 USB_DEVICE — USB 打印机

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

USB_DEVICE — USB 打印机

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/usb_device/printer/src/main.c

功能简介

本示例演示 USB 设备模式 — USB 打印机。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "printer_class.h"
#include "printer_desc.h"
#include "usbd_int.h"

int main(void)
{
  uint32_t rx_len = 0;
  
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &printer_class_handler, &printer_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    /* get usb printer receive data */
    rx_len = usb_printer_get_rxdata(&usb_core_dev, usb_buffer);
    UNUSED(rx_len);

    /* user code ...*/
  }
}

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。

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。

AT32 USB_DEVICE — USB 大容量存储

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

USB_DEVICE — USB 大容量存储

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/usb_device/msc/src/main.c

功能简介

本示例演示 USB 设备模式 — USB 大容量存储。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "msc_class.h"
#include "msc_desc.h"
#include "usbd_int.h"

int main(void)
{
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &msc_class_handler, &msc_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
  }
}

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。

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。

AT32 USB_DEVICE — USB 键盘

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

USB_DEVICE — USB 键盘

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/usb_device/keyboard/src/main.c

功能简介

本示例演示 USB 设备模式 — USB 键盘。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "keyboard_class.h"
#include "keyboard_desc.h"
#include "usbd_int.h"

int main(void)
{
  __IO uint32_t delay_index = 0;
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

#ifdef USB_LOW_POWER_WAKUP
  /* enable pwc and bpr clock */
  crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
  button_exint_init();
  usb_low_power_wakeup_config();
#endif

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &keyboard_class_handler, &keyboard_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    if(at32_button_press() == USER_BUTTON)
    {
      if(usbd_connect_state_get(&usb_core_dev) == USB_CONN_STATE_CONFIGURED)
      {
        keyboard_send_string(&usb_core_dev, (uint8_t *)" Keyboard Demo\r\n", 16);
      }
      /* remote wakeup */
      if(usbd_connect_state_get(&usb_core_dev) == USB_CONN_STATE_SUSPENDED
        &&(usb_core_dev.remote_wakup == 1))
      {
        usbd_remote_wakeup(&usb_core_dev);
      }
    }
#ifdef USB_LOW_POWER_WAKUP
     /* enter deep sleep */
    if(((keyboard_type *)(usb_core_dev.class_handler->pdata))->hid_suspend_flag == 1)
    {
      at32_led_off(LED2);
      at32_led_off(LED3);
      at32_led_off(LED4);
      /* congfig the voltage regulator mode */
      pwc_voltage_regulate_set(PWC_REGULATOR_LOW_POWER);

      /* enter deep sleep mode */
      pwc_deep_sleep_mode_enter(PWC_DEEP_SLEEP_ENTER_WFI);
      /* wait 3 LICK cycles to ensure clock stable, delay 120us*/
      /* when wakeup from deepsleep,system clock source changes to HICK */
      if((CRM->misc3_bit.hick_to_sclk == TRUE) && (CRM->misc1_bit.hickdiv == TRUE))
      {
        /* HICK is 48MHz */
        for(delay_index = 0; delay_index < 750; delay_index++)
        {
          __NOP();
        }
      }
      else
      {
        /* HICK is 8MHz */
        for(delay_index = 0; delay_index < 125; delay_index++)
        {
          __NOP();
        }
      }

      system_clock_recover();
      ((keyboard_type *)(usb_core_dev.class_handler->pdata))->hid_suspend_flag = 0;
      at32_led_on(LED2);
      at32_led_on(LED3);
      at32_led_on(LED4);
    }
#endif
  }
}

void button_exint_init(void)
{
  exint_init_type exint_init_struct;

  crm_periph_clock_enable(CRM_IOMUX_PERIPH_CLOCK, TRUE);
  gpio_exint_line_config(GPIO_PORT_SOURCE_GPIOA, GPIO_PINS_SOURCE0);

  exint_default_para_init(&exint_init_struct);
  exint_init_struct.line_enable = TRUE;
  exint_init_struct.line_mode = EXINT_LINE_INTERRUPT;
  exint_init_struct.line_select = EXINT_LINE_0;
  exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
  exint_init(&exint_init_struct);

  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);
  nvic_irq_enable(EXINT0_IRQn, 0, 0);
}

void usb_low_power_wakeup_config(void)
{
  exint_init_type exint_init_struct;

  exint_default_para_init(&exint_init_struct);

  exint_init_struct.line_enable = TRUE;
  exint_init_struct.line_mode = EXINT_LINE_INTERRUPT;
  exint_init_struct.line_select = EXINT_LINE_18;
  exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
  exint_init(&exint_init_struct);

  nvic_irq_enable(USBFSWakeUp_IRQn, 0, 0);
}

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。

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。

AT32 USB_DEVICE — USB 鼠标

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

USB_DEVICE — USB 鼠标

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/usb_device/mouse/src/main.c

功能简介

本示例演示 USB 设备模式 — USB 鼠标。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "mouse_class.h"
#include "mouse_desc.h"
#include "usbd_int.h"

int main(void)
{
  __IO uint32_t delay_index = 0;
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

#ifdef USB_LOW_POWER_WAKUP
  /* enable pwc and bpr clock */
  crm_periph_clock_enable(CRM_PWC_PERIPH_CLOCK, TRUE);
  button_exint_init();
  usb_low_power_wakeup_config();
#endif

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &mouse_class_handler, &mouse_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    if(at32_button_press() == USER_BUTTON)
    {
      if(usbd_connect_state_get(&usb_core_dev) == USB_CONN_STATE_CONFIGURED)
      {
        usb_hid_mouse_send(&usb_core_dev, RIGHT_BUTTON);
        press_mouse = 1;
      }
      /* remote wakeup */
      if(usbd_connect_state_get(&usb_core_dev) == USB_CONN_STATE_SUSPENDED
        &&(usb_core_dev.remote_wakup == 1))
      {
        usbd_remote_wakeup(&usb_core_dev);
      }
    }
    else if(press_mouse == 1)
    {
      delay_ms(10);
      usb_hid_mouse_send(&usb_core_dev, BUTTON_RELEASE);
      press_mouse = 0;
    }
 #ifdef USB_LOW_POWER_WAKUP
     /* enter deep sleep */
    if(((mouse_type *)(usb_core_dev.class_handler->pdata))->hid_suspend_flag == 1)
    {
      at32_led_off(LED2);
      at32_led_off(LED3);
      at32_led_off(LED4);
      /* congfig the voltage regulator mode */
      pwc_voltage_regulate_set(PWC_REGULATOR_LOW_POWER);

      /* enter deep sleep mode */
      pwc_deep_sleep_mode_enter(PWC_DEEP_SLEEP_ENTER_WFI);
      /* wait 3 LICK cycles to ensure clock stable, delay 120us*/
      /* when wakeup from deepsleep,system clock source changes to HICK */
      if((CRM->misc3_bit.hick_to_sclk == TRUE) && (CRM->misc1_bit.hickdiv == TRUE))
      {
        /* HICK is 48MHz */
        for(delay_index = 0; delay_index < 750; delay_index++)
        {
          __NOP();
        }
      }
      else
      {
        /* HICK is 8MHz */
        for(delay_index = 0; delay_index < 125; delay_index++)
        {
          __NOP();
        }
      }

      system_clock_recover();
      ((mouse_type *)(usb_core_dev.class_handler->pdata))->hid_suspend_flag = 0;
      at32_led_on(LED2);
      at32_led_on(LED3);
      at32_led_on(LED4);
    }
#endif

  }
}

void button_exint_init(void)
{
  exint_init_type exint_init_struct;

  crm_periph_clock_enable(CRM_IOMUX_PERIPH_CLOCK, TRUE);
  gpio_exint_line_config(GPIO_PORT_SOURCE_GPIOA, GPIO_PINS_SOURCE0);

  exint_default_para_init(&exint_init_struct);
  exint_init_struct.line_enable = TRUE;
  exint_init_struct.line_mode = EXINT_LINE_INTERRUPT;
  exint_init_struct.line_select = EXINT_LINE_0;
  exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
  exint_init(&exint_init_struct);

  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);
  nvic_irq_enable(EXINT0_IRQn, 0, 0);
}

void usb_low_power_wakeup_config(void)
{
  exint_init_type exint_init_struct;

  exint_default_para_init(&exint_init_struct);

  exint_init_struct.line_enable = TRUE;
  exint_init_struct.line_mode = EXINT_LINE_INTERRUPT;
  exint_init_struct.line_select = EXINT_LINE_18;
  exint_init_struct.line_polarity = EXINT_TRIGGER_RISING_EDGE;
  exint_init(&exint_init_struct);

  nvic_irq_enable(USBFSWakeUp_IRQn, 0, 0);
}

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。

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。

延时：使用系统延时函数控制 LED 翻转间隔。

AT32 USB_DEVICE — USB 音频

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

USB_DEVICE — USB 音频

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/usb_device/audio/src/main.c

功能简介

本示例演示 USB 设备模式 — USB 音频。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "audio_class.h"
#include "audio_desc.h"
#include "usbd_int.h"
#include "audio_codec.h"

int main(void)
{
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  /* system clock config */
  system_clock_config();

  /* audio codec init */
  audio_codec_init();

  /* at32 board init */
  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &audio_class_handler, &audio_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    audio_codec_loop();
    delay_ms(100);
  }
}

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。

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。

延时：使用系统延时函数控制 LED 翻转间隔。

AT32 USB_DEVICE — WinUSB

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

USB_DEVICE — WinUSB

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/usb_device/winusb/src/main.c

功能简介

本示例演示 USB 设备模式 — WinUSB。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "winusb_class.h"
#include "winusb_desc.h"
#include "usbd_int.h"

int main(void)
{
  uint16_t data_len;

  uint32_t timeout;

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

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &winusb_class_handler, &winusb_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

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

    if(data_len > 0)
    {

      /* 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
      */
      timeout = 5000000;
      do
      {
        /* send data to host */
        if(usb_winusb_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。

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。

AT32 USB_DEVICE — 复合设备: VCP + MSC

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

USB_DEVICE — 复合设备: VCP + MSC

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/usb_device/composite_vcp_msc/src/main.c

功能简介

本示例演示 USB 设备模式 — 复合设备: VCP + MSC。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "cdc_msc_class.h"
#include "cdc_msc_desc.h"
#include "usbd_int.h"

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);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &cdc_msc_class_handler, &cdc_msc_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  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。

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。

AT32 USB_DEVICE — 复合设备: VCP + 键盘

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

USB_DEVICE — 复合设备: VCP + 键盘

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/usb_device/composite_vcp_keyboard/src/main.c

功能简介

本示例演示 USB 设备模式 — 复合设备: VCP + 键盘。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "cdc_keyboard_class.h"
#include "cdc_keyboard_desc.h"
#include "usbd_int.h"

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);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &cdc_keyboard_class_handler, &cdc_keyboard_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    /* get usb vcp receive data */
    data_len = usb_vcpkybrd_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_vcpkybrd_vcp_send_data(&usb_core_dev, usb_buffer, data_len) == SUCCESS)
        {
          break;
        }
      }while(timeout --);
    }

    if(at32_button_press() == USER_BUTTON)
    {
      keyboard_send_string(&usb_core_dev, (uint8_t *)" Keyboard Demo\r\n", 16);
    }
  }
}

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。

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。

AT32 USB_DEVICE — 复合设备: 音频 + HID

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

USB_DEVICE — 复合设备: 音频 + HID

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/usb_device/composite_audio_hid/src/main.c

功能简介

本示例演示 USB 设备模式 — 复合设备: 音频 + HID。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "usbd_int.h"
#include "audio_hid_class.h"
#include "audio_hid_desc.h"
#include "audio_codec.h"

int main(void)
{
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  /* system clock config */
  system_clock_config();

  /* audio codec init */
  audio_codec_init();

  /* at32 board init */
  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &audio_hid_class_handler, &audio_hid_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    audio_codec_loop();
    if(at32_button_press() == USER_BUTTON)
    {
      report_buf[0] = HID_REPORT_ID_5;
      report_buf[1] = (~report_buf[1]) & 0x1;
      audio_hid_class_send_report(&usb_core_dev, report_buf, USBD_AUHID_IN_MAXPACKET_SIZE);
    }
    delay_ms(100);
  }
}

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。

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。

延时：使用系统延时函数控制 LED 翻转间隔。

AT32 USB_DEVICE — 虚拟 MSC + IAP

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

USB_DEVICE — 虚拟 MSC + IAP

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/usb_device/virtual_msc_iap/src/main.c

功能简介

本示例演示 USB 设备模式 — 虚拟 MSC + IAP。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "msc_class.h"
#include "msc_desc.h"
#include "usbd_int.h"
#include "flash_fat16.h"

int main(void)
{
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  flash_fat16_init();

  at32_board_init();

  if(flash_fat16_get_upgrade_flag() == IAP_SUCCESS &&
    (at32_button_press() == NO_BUTTON))
  {
    jump_to_app(flash_iap.flash_app_addr);
  }

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &msc_class_handler, &msc_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    flash_fat16_loop_status();
  }
}

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。

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。

AT32 USB_DEVICE — 虚拟串口 (VCP)

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

USB_DEVICE — 虚拟串口 (VCP)

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/usb_device/virtual_comport/src/main.c

功能简介

本示例演示 USB 设备模式 — 虚拟串口 (VCP)。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

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 usb_usart_config(linecoding_type linecoding);
void usart_gpio_config(void);
#define  usart_buffer_size  2048
uint8_t usart_rx_buffer[usart_buffer_size];
uint16_t hw_usart_rx_index = 0;
uint16_t hw_usart_read_index = 0;
uint16_t usart_rx_data_len = 0;
uint16_t ov_cnt = 0;
void usart_send_data(uint8_t *send_data, uint16_t len);
uint16_t usart_receive_data(void);

/**
  * @brief  usb 48M clock select
  * @param  clk_s:USB_CLK_HICK, USB_CLK_HEXT
  * @retval none
  */
void usb_clock48m_select(usb_clk48_s clk_s)
{
  crm_clocks_freq_type clocks_struct;
  
  if(clk_s == USB_CLK_HICK)
  {
    crm_usb_clock_source_select(CRM_USB_CLOCK_SOURCE_HICK);

    /* enable the acc calibration ready interrupt */
    crm_periph_clock_enable(CRM_ACC_PERIPH_CLOCK, TRUE);

    /* update the c1\c2\c3 value */
    acc_write_c1(7980);
    acc_write_c2(8000);
    acc_write_c3(8020);

    /* open acc calibration */
    acc_calibration_mode_enable(ACC_CAL_HICKTRIM, TRUE);
  }
  else
  {
    crm_clocks_freq_get(&clocks_struct);
    switch(clocks_struct.sclk_freq)
    {
      /* 48MHz */
      case 48000000:
        crm_usb_clock_div_set(CRM_USB_DIV_1);
        break;

      /* 72MHz */
      case 72000000:
        crm_usb_clock_div_set(CRM_USB_DIV_1_5);
        break;

      /* 96MHz */
      case 96000000:
        crm_usb_clock_div_set(CRM_USB_DIV_2);
        break;

      /* 120MHz */
      case 120000000:
        crm_usb_clock_div_set(CRM_USB_DIV_2_5);
        break;

      /* 144MHz */
      case 144000000:
        crm_usb_clock_div_set(CRM_USB_DIV_3);
        break;

      /* 168MHz */
      case 168000000:
        crm_usb_clock_div_set(CRM_USB_DIV_3_5);
        break;

      /* 192MHz */
      case 192000000:
        crm_usb_clock_div_set(CRM_USB_DIV_4);
        break;

      default:
        break;

    }
  }
}

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);

  system_clock_config();

  at32_board_init();

  /* usart gpio config */
  usart_gpio_config();

  /* hardware usart config: usart2 */
  usb_usart_config(linecoding);

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &cdc_class_handler, &cdc_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

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

    /* send data to hardware usart */
    if(data_len > 0)
    {
      usart_send_data(usb_buffer, data_len);
    }

    /* if hardware usart received data,usb send data to host */
    usart_rx_data_len = usart_receive_data();
    if(usart_rx_data_len || send_zero_packet == 1)
    {
      if(usart_rx_data_len > 0)
        send_zero_packet = 1;

      if(usart_rx_data_len == 0)
        send_zero_packet = 0;

      timeout = 50000;

      if((hw_usart_read_index + usart_rx_data_len) < usart_buffer_size)
      {
        do
        {
          /* send data to host */
          if(usb_vcp_send_data(&usb_core_dev, &usart_rx_buffer[hw_usart_read_index], usart_rx_data_len) == SUCCESS)
          {
            hw_usart_read_index = hw_usart_read_index + usart_rx_data_len;

            break;
          }
        }while(timeout --);

      }
      /* process the fifo overflow */
      else
      {
        do
        {
          /* send data to host */
          if(usb_vcp_send_data(&usb_core_dev, &usart_rx_buffer[hw_usart_read_index], usart_buffer_size - hw_usart_read_index) == SUCCESS)
          {
            /* get fifo overflow data count */
            ov_cnt = usart_rx_data_len - (usart_buffer_size - hw_usart_read_index);
            hw_usart_read_index = 0;
            break;
          }
        }while(timeout --);
        timeout = 50000;
        do
        {
          /* send data to host */
          if(usb_vcp_send_data(&usb_core_dev, &usart_rx_buffer[hw_usart_read_index], ov_cnt) == SUCCESS)
          {
            hw_usart_read_index = ov_cnt;
            break;
          }
        }while(timeout --);
      }
    }
  }
}

void usb_usart_config( linecoding_type linecoding)
{
  usart_stop_bit_num_type usart_stop_bit;
  usart_data_bit_num_type usart_data_bit;
  usart_parity_selection_type usart_parity_select;

  /* enable the usart2 and gpio clock */
  crm_periph_clock_enable(CRM_USART2_PERIPH_CLOCK, FALSE);
  crm_periph_clock_enable(CRM_USART2_PERIPH_CLOCK, TRUE);

  /* stop bit */
  switch(linecoding.format)
  {
    case 0x0:
      usart_stop_bit = USART_STOP_1_BIT;
      break;
  /* to be used when transmitting and receiving data in smartcard mode */
    case 0x1:
      usart_stop_bit = USART_STOP_1_5_BIT;
      break;
    case 0x2:
      usart_stop_bit = USART_STOP_2_BIT;
      break;
    default :
      break;
  }

  /* parity */
  switch(linecoding.parity)
  {
    case 0x0:
      usart_parity_select = USART_PARITY_NONE;
      break;
    case 0x1:
      usart_parity_select = USART_PARITY_ODD;
      break;
    case 0x2:
      usart_parity_select = USART_PARITY_EVEN;
      break;
    /* hardware usart not support partiy for mark and space */
    case 0x3:
    case 0x4:
      break;
    default :
      break;
  }

  if(USART_PARITY_NONE == usart_parity_select)
  {
    /* data bits */
    switch(linecoding.data)
    {
      /* hardware usart not support data bits for 5/6/7 */
      case 0x5:
      case 0x6:
      case 0x7:
        break;
      case 0x8:
        usart_data_bit = USART_DATA_8BITS;
        break;
      /* hardware usart not support data bits for 16 */
      case 0x10:
        break;
      default :
        break;
    }
  }
  else
  {
    /* data bits */
    switch(linecoding.data)
    {
      /* hardware usart not support data bits for 5/6 */
      case 0x5:
      case 0x6:
        break;
      case 0x7:
        usart_data_bit = USART_DATA_8BITS;
        break;
      case 0x8:
        usart_data_bit = USART_DATA_9BITS;
        break;
      /* hardware usart not support data bits for 16 */
      case 0x10:
        break;
      default :
        break;
    }
  }

  nvic_irq_enable(USART2_IRQn, 0, 0);

  /* configure usart2 param */
  usart_init(USART2, linecoding.bitrate, usart_data_bit, usart_stop_bit);
  usart_parity_selection_config(USART2, usart_parity_select);
  usart_transmitter_enable(USART2, TRUE);
  usart_receiver_enable(USART2, TRUE);

  /* enable usart2 interrupt */
  usart_interrupt_enable(USART2, USART_RDBF_INT, TRUE);
  usart_enable(USART2, TRUE);
}

void usart_gpio_config(void)
{
  gpio_init_type gpio_init_struct;
  crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);

  /* configure the usart2 tx pin */
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init_struct.gpio_out_type  = GPIO_OUTPUT_PUSH_PULL;
  gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
  gpio_init_struct.gpio_pins = GPIO_PINS_2;
  gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
  gpio_init(GPIOA, &gpio_init_struct);

  /* configure the usart2 rx pin */
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init_struct.gpio_out_type  = GPIO_OUTPUT_PUSH_PULL;
  gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
  gpio_init_struct.gpio_pins = GPIO_PINS_3;
  gpio_init_struct.gpio_pull = GPIO_PULL_UP;
  gpio_init(GPIOA, &gpio_init_struct);
}

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。

AT32 USB_DEVICE — 虚拟串口回环

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

USB_DEVICE — 虚拟串口回环

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/usb_device/vcp_loopback/src/main.c

功能简介

本示例演示 USB 设备模式 — 虚拟串口回环。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

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"

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);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &cdc_class_handler, &cdc_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  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。

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。

AT32 USB_DEVICE — 自定义 HID

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

USB_DEVICE — 自定义 HID

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/usb_device/custom_hid/src/main.c

功能简介

本示例演示 USB 设备模式 — 自定义 HID。MCU 作为 USB 设备连接到电脑，实现 HID 键盘/鼠标、虚拟串口（CDC）、大容量存储（MSC）等功能。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"
#include "usbd_core.h"
#include "custom_hid_class.h"
#include "custom_hid_desc.h"
#include "usbd_int.h"

int main(void)
{
  /* config nvic priority group */
  nvic_priority_group_config(NVIC_PRIORITY_GROUP_4);

  system_clock_config();

  at32_board_init();

  /* select usb 48m clcok source */
  usb_clock48m_select(USB_CLK_HEXT);

  /* enable usb clock */
  crm_periph_clock_enable(CRM_USB_PERIPH_CLOCK, TRUE);

  /* enable usb interrupt */
  nvic_irq_enable(USBFS_L_CAN1_RX0_IRQn, 0, 0);

  /* usb core init */
  usbd_core_init(&usb_core_dev, USB, &custom_hid_class_handler, &custom_hid_desc_handler, 0);

  /* enable usb pull-up */
  usbd_connect(&usb_core_dev);

  while(1)
  {
    if(at32_button_press() == USER_BUTTON)
    {
      report_buf[1] = (~report_buf[1]) & 0x1;
      report_buf[0] = HID_REPORT_ID_5;
      custom_hid_class_send_report(&usb_core_dev, report_buf, USBD_CUSTOM_IN_MAXPACKET_SIZE);

    }
  }
}

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。

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。