AT32 TMR — 7 路 PWM 输出

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

TMR — 7 路 PWM 输出

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/tmr/7_pwm_output/src/main.c

功能简介

本示例演示定时器 PWM 输出。通过配置定时器的周期和比较值，输出指定频率和占空比的方波。LED 亮度调节、电机控制、蜂鸣器驱动都要用到 PWM。

完整代码

#include "at32f403a_407_board.h"
#include "at32f403a_407_clock.h"

int main(void)
{
  system_clock_config();

  at32_board_init();

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

  /* turn led2/led3/led4 on */
  at32_led_on(LED2);
  at32_led_on(LED3);
  at32_led_on(LED4);

  /* enable tmr1/gpioa/gpiob clock */
  crm_periph_clock_enable(CRM_TMR1_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_GPIOA_PERIPH_CLOCK, TRUE);
  crm_periph_clock_enable(CRM_GPIOB_PERIPH_CLOCK, TRUE);

  /* timer1 output pin Configuration */
  gpio_init_struct.gpio_pins = GPIO_PINS_8 | GPIO_PINS_9 | GPIO_PINS_10 | GPIO_PINS_11;
  gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
  gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
  gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init(GPIOA, &gpio_init_struct);

  gpio_init_struct.gpio_pins = GPIO_PINS_13 | GPIO_PINS_14 | GPIO_PINS_15;
  gpio_init_struct.gpio_mode = GPIO_MODE_MUX;
  gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
  gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init(GPIOB, &gpio_init_struct);

  gpio_init_struct.gpio_pins = GPIO_PINS_12;
  gpio_init_struct.gpio_mode = GPIO_MODE_INPUT;
  gpio_init_struct.gpio_out_type = GPIO_OUTPUT_PUSH_PULL;
  gpio_init_struct.gpio_pull = GPIO_PULL_NONE;
  gpio_init_struct.gpio_drive_strength = GPIO_DRIVE_STRENGTH_STRONGER;
  gpio_init(GPIOB, &gpio_init_struct);


  /* tmr1 configuration generate 7 pwm signals with 4 different duty cycles:
   prescaler = 0, tmr1 counter clock = system_core_clock

   the objective is to generate 7 pwm signal at 17.57 khz:
     - tim1_period = (system_core_clock / 17570) - 1
   the channel 1 and channel 1n duty cycle is set to 50%
   the channel 2 and channel 2n duty cycle is set to 37.5%
   the channel 3 and channel 3n duty cycle is set to 25%
   the channel 4 duty cycle is set to 12.5%
   the timer pulse is calculated as follows:
     - channelxpulse = duty_cycle * (tim1_period - 1) / 100 */

  /* compute the value to be set in arr regiter to generate signal frequency at 17.57 khz */
  timer_period = (crm_clocks_freq_struct.sclk_freq / 17570 ) - 1;

  /* compute ccr1 value to generate a duty cycle at 50% for channel 1 and 1n */
  channel1_pulse = (uint16_t)(((uint32_t) 5 * (timer_period - 1)) / 10);

  /* compute ccr2 value to generate a duty cycle at 37.5%  for channel 2 and 2n */
  channel2_pulse = (uint16_t)(((uint32_t) 375 * (timer_period - 1)) / 1000);

  /* compute ccr3 value to generate a duty cycle at 25%  for channel 3 and 3n */
  channel3_pulse = (uint16_t)(((uint32_t) 25 * (timer_period - 1)) / 100);

  /* compute ccr4 value to generate a duty cycle at 12.5%  for channel 4 */
  channel4_pulse = (uint16_t)(((uint32_t) 125 * (timer_period- 1)) / 1000);

  tmr_base_init(TMR1, timer_period, 0);
  tmr_cnt_dir_set(TMR1, TMR_COUNT_UP);

  /* channel 1, 2, 3 and 4 configuration in output mode */
  tmr_output_default_para_init(&tmr_output_struct);
  tmr_output_struct.oc_mode = TMR_OUTPUT_CONTROL_PWM_MODE_B;
  tmr_output_struct.oc_output_state = TRUE;
  tmr_output_struct.oc_polarity = TMR_OUTPUT_ACTIVE_LOW;
  tmr_output_struct.oc_idle_state = TRUE;
  tmr_output_struct.occ_output_state = TRUE;
  tmr_output_struct.occ_polarity = TMR_OUTPUT_ACTIVE_HIGH;
  tmr_output_struct.occ_idle_state = FALSE;

  /* channel 1 */
  tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_1, &tmr_output_struct);
  tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_1, channel1_pulse);

  /* channel 2 */
  tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_2, &tmr_output_struct);
  tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_2, channel2_pulse);

  /* channel 3 */
  tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_3, &tmr_output_struct);
  tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_3, channel3_pulse);

  /* channel 4 */
  tmr_output_channel_config(TMR1, TMR_SELECT_CHANNEL_4, &tmr_output_struct);
  tmr_channel_value_set(TMR1, TMR_SELECT_CHANNEL_4, channel4_pulse);

  /* output enable */
  tmr_output_enable(TMR1, TRUE);

  /* enable tmr1 */
  tmr_counter_enable(TMR1, TRUE);

  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。

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。

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。

PWM 配置：在定时器基础上设置比较值（CCR），占空比 = CCR / (ARR+1)。CCR 越大占空比越高。

7_pwm_output on CLing

AT32 TMR — 7 路 PWM 输出

TMR — 7 路 PWM 输出

功能简介

完整代码

代码讲解