STM32PWM输出实现LED灯渐亮渐灭

/*

*说明：

*PA0:KEY1;PA1:KEY2;

*PA2:LED1;PA3:LED2;

*PA9:USART1_TX;PA10:USART1_RX

*/

#include"stm32f10x.h"

#include"stm32f10x_rcc.h"

#include"stm32f10x_gpio.h"

#include"stm32f10x_tim.h"

#include"stm32f10x_pwr.h"

#include"stm32f10x_exti.h"

#include"system_stm32f10x.h"

#include"misc.h"

voidRCC_Configuration(void);

voidGPIO_Configuration(void);

voidTIM2_Configuration(void);

voiddelay_ms(u16time);

intmain()

{

u8led_fx=1;

u16led_dt=0;

RCC_Configuration();

GPIO_Configuration();

TIM2_Configuration();

while(1)

{

delay_ms(10);

if(led_fx==1)

{

led_dt++;

}else{

led_dt--;

}

if(led_dt>100)led_fx=0;//可以和初始值一样

if(led_dt==0)led_fx=1;

TIM_SetCompare3(TIM2,led_dt);//通道3没有重影像是PA2对应LED1

TIM_SetCompare4(TIM2,led_dt);//通道4没有重影像是PA3对应LED2

}

}

voidRCC_Configuration(void)

{

SystemInit();

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

//GPIO_AFIODeInit();和下面相同效果，可以查看源码证明

RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

}

voidGPIO_Configuration(void)

{

GPIO_InitTypeDefGPIO_InitStructure;

//GPIO_PinRemapConfig(GPIO_PartialRemap2_TIM2,ENABLE);//端口映射函数

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_2|GPIO_Pin_3;//GPIO_Pin_3对应channel3，主函数改为：TIM_SetCompare3

GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;

GPIO_Init(GPIOA,&GPIO_InitStructure);

}

voidTIM2_Configuration(void)

{

TIM_TimeBaseInitTypeDefTIM_TimeBaseStructure;

TIM_OCInitTypeDefTIM_OCInitStructure;

TIM_DeInit(TIM2);

TIM_InternalClockConfig(TIM2);

//定时器初始化

TIM_TimeBaseStructure.TIM_Period=100-1;//初始值是100,2MHz=2000KHz,2MHz/100=0.02MHz,所有周期T=1/0.02MHz=50us,示波器显示周期应该为50us

TIM_TimeBaseStructure.TIM_Prescaler=36-1;//36倍分频，72MHz/36=2MHz

TIM_TimeBaseStructure.TIM_ClockDivision=0;

TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;

TIM_TimeBaseStructure.TIM_RepetitionCounter=0;

TIM_TimeBaseInit(TIM2,&TIM_TimeBaseStructure);

//PWM初始化

TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;

TIM_OCInitStructure.TIM_Pulse=50;//占空比值是50，所以占空比是：50/100=50%

TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_Low;

TIM_OC3Init(TIM2,&TIM_OCInitStructure);

TIM_OCInitStructure.TIM_Pulse=20;

TIM_OC4Init(TIM2,&TIM_OCInitStructure);

//TIM_OC3PreloadConfig(TIM2,TIM_OCPreload_Enable);

//TIM_ARRPreloadConfig(TIM2,ENABLE);

TIM_Cmd(TIM2,ENABLE);

TIM_CtrlPWMOutputs(TIM2,ENABLE);

}

voiddelay_ms(u16time)

{

u16i=0;

while(time--)

{

i=12000;

while(i--);

}

}