TIM-高级定时器

本篇总结

使用 TIM3，输出 PWM 波形。

硬件平台：本例程基于 W55MH32L-EVB 开发板运行。

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void TIM_Configuration(void)
{
    GPIO_InitTypeDef        GPIO_InitStructure;
    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_OCInitTypeDef       TIM_OCInitStructure;

    /* 开启 TIM3 及 GPIOA/AFIO 时钟 */
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

    /* PA7: TIM3_CH2 → 复用推挽输出 */
    GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* 时基：PSC 使 CK_CNT=1MHz，ARR=99 → PWM 周期 100μs（10kHz） */
    TIM_TimeBaseStructure.TIM_Period        = 99;
    TIM_TimeBaseStructure.TIM_Prescaler     = clocks.SYSCLK_Frequency / 1000000 - 1;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode   = TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

    /* 输出比较：PWM2 模式，CH2，Pulse=49 → 占空比 49%，低电平有效 */
    TIM_OCInitStructure.TIM_OCMode       = TIM_OCMode_PWM2;
    TIM_OCInitStructure.TIM_OutputState  = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable;
    TIM_OCInitStructure.TIM_Pulse        = 99 / 2;
    TIM_OCInitStructure.TIM_OCPolarity   = TIM_OCPolarity_Low;
    TIM_OCInitStructure.TIM_OCNPolarity  = TIM_OCNPolarity_Low;
    TIM_OCInitStructure.TIM_OCIdleState  = TIM_OCIdleState_Set;
    TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;
    TIM_OC2Init(TIM3, &TIM_OCInitStructure);

    /* 使能预装载寄存器：运行中改 CCR/ARR 会在下个更新事件生效 */
    TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
    TIM_ARRPreloadConfig(TIM3, ENABLE);

    /* 启动定时器 + 使能主输出 */
    TIM_Cmd(TIM3, ENABLE);
    TIM_CtrlPWMOutputs(TIM3, ENABLE);
}

如果你想自定义

• 改 PWM 频率 → 修改 TIM_Period（ARR）和 TIM_Prescaler（PSC）。如要 1kHz：PSC=71（1MHz）、ARR=999
• 改占空比 → 修改 TIM_Pulse（CCR）。如要 30% 占空比：TIM_Pulse = 99 * 3 / 10（即 29）
• 换用 CH1/CH3/CH4 → 同步修改 GPIO 引脚（CH1=PA6、CH3=PA8、CH4=PA9）和 TIM_OCxInit / TIM_OCxPreloadConfig 的通道号

void RCC_ClkConfiguration(void)
{
    RCC_DeInit();

    RCC_HSEConfig(RCC_HSE_ON);
    while (RCC_GetFlagStatus(RCC_FLAG_HSERDY) == RESET);

    RCC_PLLCmd(DISABLE);
    RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9); /* HSE 8MHz × 9 = 72MHz */

    RCC_PLLCmd(ENABLE);
    while (RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET);

    RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);

    RCC_HCLKConfig(RCC_SYSCLK_Div1);
    RCC_PCLK1Config(RCC_HCLK_Div2);
    RCC_PCLK2Config(RCC_HCLK_Div1);

    RCC_LSICmd(ENABLE);
    while (RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET);
    RCC_HSICmd(ENABLE);
    while (RCC_GetFlagStatus(RCC_FLAG_HSIRDY) == RESET);
}

RCC_ClocksTypeDef clocks;

int main(void)
{
    RCC_ClkConfiguration();
    delay_init();
    UART_Configuration(115200);
    RCC_GetClocksFreq(&clocks);

    printf("SYSCLK: %3.1fMhz, HCLK: %3.1fMhz, PCLK1: %3.1fMhz, "
           "PCLK2: %3.1fMhz, ADCCLK: %3.1fMhz\n",
           (float)clocks.SYSCLK_Frequency / 1000000,
           (float)clocks.HCLK_Frequency / 1000000,
           (float)clocks.PCLK1_Frequency / 1000000,
           (float)clocks.PCLK2_Frequency / 1000000,
           (float)clocks.ADCCLK_Frequency / 1000000);
    printf("TIM Out Test.\n");

    TIM_Configuration();

    while (1);
}

int SER_PutChar(int ch)
{
    while (!USART_GetFlagStatus(USART_TEST, USART_FLAG_TC));
    USART_SendData(USART_TEST, (uint8_t)ch);
    return ch;
}

int fputc(int c, FILE *f)
{
    if (c == '\n')
        SER_PutChar('\r');         // 补回车，确保串口工具正确换行
    return (SER_PutChar(c));
}