mini32中利用TIM3的CH1和CH2产生2路PWM输出，分别对应LED1和LED0，为什么灯只会变亮不会变暗，各位大神，求解答

聆听几点几 · 发表于 2015-4-21 21:41:17

[mw_shl_code=c,true]void PWM_Init(u16 arr,u16 psc) { GPIO_InitTypeDef GPIO_InitStructure; TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure; TIM_OCInitTypeDef TIM_OCInitStructure; //pwm shuchuhanshu RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE); RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD,ENABLE); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOA, &GPIO_InitStructure); GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING; GPIO_Init(GPIOD, &GPIO_InitStructure); 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); GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6; GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_Init(GPIOA, &GPIO_InitStructure); //GPIO_SetBits(GPIOB,GPIO_Pin_7);*/ //设置Tim3——ch2重映射到pb5上 //GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3,ENABLE); // 初始化Tim3设置Tim3的arr值和PSC值 TIM_TimeBaseStructure.TIM_Period=arr; TIM_TimeBaseStructure.TIM_Prescaler=psc; TIM_TimeBaseStructure.TIM_ClockDivision=0; TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up; TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure); //设置Tim3——ch1的PWM模式，使能Tim3的ＣＨ1 TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1; TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值 TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High; TIM_OC1Init(TIM3,&TIM_OCInitStructure); TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIMx在CCR1上的预装载寄存器 //设置Tim3——ch2的PWM模式，使能Tim3的ＣＨ２ TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM2; TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable; TIM_OCInitStructure.TIM_Pulse = 0; //设置待装入捕获比较寄存器的脉冲值 TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High; TIM_OC2Init(TIM3,&TIM_OCInitStructure); TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable); //使能TIMx在CCR2上的预装载寄存器 TIM_ARRPreloadConfig(TIM3, ENABLE); //使能TIMx在ARR上的预装载寄存器 //使能Tim3 TIM_Cmd(TIM3,ENABLE); } #include "led.h" #include "delay.h" #include "sys.h" #include "key.h" #include "usart.h" #include "exti.h" #include"timer.h" //Mini STM32开发板范例代码4 //外部中断实验 //正点原子@ALIENTEK //技术论坛:www.openedv.com //注意,此代码还是无法进行SWD仿真!因为使用了中断,没法用普通的方法来考虑间歇复用SWD口! int main(void) { led0pwmval=0; u16 led1pwmval=0; u8 dir=1; SystemInit(); delay_init(72); //延时初始化 NVIC_Configuration(); uart_init(9600); //串口初始化 LED_Init(); //LED端口初始化 Timerx_Init(5000,7199); //外部中断初始化 PWM_Init(900,0); while(1) { delay_ms(10); if(dir) { led0pwmval++; led1pwmval++; } else { led0pwmval--; led1pwmval--; } if(led0pwmval>300&&led1pwmval>300) dir=0; if(led1pwmval==0&&led1pwmval==0) dir=1; TIM_SetCompare1(TIM3,led1pwmval); TIM_SetCompare2(TIM3,led0pwmval); } } [/mw_shl_code]