stm32f103c8t6定时器1PWM怎么写

首先，需要配置定时器1为PWM输出模式，具体操作如下：

1. 使能TIM1时钟，同时使能GPIOB时钟。

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1 | RCC_APB2Periph_GPIOB, ENABLE);

2. 配置GPIOB的引脚为TIM1的PWM输出，比如将PB8配置为TIM1_CH2输出。

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);

3. 配置TIM1为PWM模式。这里以PWM模式1为例，同时需要设置TIM1的时钟分频、重载值、占空比等参数。

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

// 设置TIM1的时钟分频、重载值等参数
TIM_TimeBaseStructure.TIM_Period = 2000 - 1; // PWM周期为2ms
TIM_TimeBaseStructure.TIM_Prescaler = 72 - 1; // 时钟分频系数为72，时钟频率为72MHz
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM1, &TIM_TimeBaseStructure);

// 配置TIM1_CH2为PWM输出
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 1000; // 设置占空比为50%
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC2Init(TIM1, &TIM_OCInitStructure);

// 使能TIM1_CH2的PWM输出
TIM_CCPreloadControl(TIM1, ENABLE);
TIM_Cmd(TIM1, ENABLE);

最后，就可以通过改变TIM1_CH2的占空比来实现PWM输出的改变。比如，将占空比设置为75%：

TIM_SetCompare2(TIM1, 1500);