求助求助！！！关于pwm波的！！！求指导。。。。真心求。。。

z6115913 提问时间：2011-12-11 10:48 /

/*这个是我自己写的四个通道的代码，我想通过通道2来控制PA7的led渐亮和渐暗，不过不知道为什么不行，跪求各位达人帮我看看，当然是有空的话。。。*/
#include "stm32f10x.h"
#include

#include
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
uint16_t CCR1_Val = 300;
uint16_t CCR2_Val = 0;
uint16_t CCR3_Val = 750;
uint16_t CCR4_Val = 0;
uint16_t PrescalerValue = 0;

//void RCC_Configuration(void);                //时钟配置
//void GPIO_Configuration(void);          //管脚配置
void Delay (__IO uint32_t nCount);       //延时函数

int main(void)
{
uint16_t dir=1;
RCC_open();
//GPIO_Configuration();
GPIO_open();
PrescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
TIM_TimeBaseStructure.TIM_Period = 900;                               //周期
//TIM_TimeBaseStructure.TIM_P.rescaler = PrescalerValue;             //分频
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;                            //时钟分割
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //计数模式，向上计数

TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);                   //初始TIM3
/*************************** 通道1 ********************************/
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //PWM2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //PWM功能使能
TIM_OCInitStructure.TIM_Pulse = CCR1_Val;                         //写比较值(占空比
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //置高
TIM_OC1Init(TIM3, &TIM_OCInitStructure);    //选择1通道
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);    //一通道使能
/****************************** 通道2 ******************************/
/*PWM1 Mode configuration: Channel2 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR2_Val;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;
//TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High;
TIM_OC2Init(TIM3, &TIM_OCInitStructure);
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);
/******************************* 通道3 *********************************/
/* PWM1 Mode configuration: Channel3 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR3_Val;
TIM_OC3Init(TIM3, &TIM_OCInitStructure);
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable);
/****************************** 通道4 *********************************/
/* PWM1 Mode configuration: Channel4 */
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = CCR4_Val;
TIM_OC4Init(TIM3, &TIM_OCInitStructure);
TIM_OC4PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE);                      //
TIM_Cmd(TIM3, ENABLE);                                        //使能计数
while (1)
{
/*CCR3_Val++;
if(CCR3_Val==1000)CCR3_Val=0;
TIM_SetCompare3(TIM3,CCR3_Val);                      //占空比调节

Delay(0xFfff);
*/
if(dir)
CCR2_Val++;
else
CCR2_Val--;
if(CCR2_Val>300)
dir=0;
if(CCR2_Val==0)
dir=1;

TIM_SetCompare3(TIM3,CCR2_Val);
Delay(0xFfff); //为什么要延时这么久？
}
}
/*************************** 时钟配置 *******************************/
/*void RCC_Configuration(void)
{
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);          //T3时钟使能
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB |
                     RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
            //管脚时钟
} */
/************************** 管脚配置 ******************************/

/*void GPIO_Configuration(void)
{
GPIO_InitTypeDef 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 = 0x7fff;
GPIO_Init(GPIOB, &GPIO_InitStructure);

}  */
/************************** 延时函数 ******************************/
void Delay (__IO uint32_t nCount)
{
for(; nCount != 0; nCount--);
}

//子函数
#include
void GPIO_open(void)
{
GPIO_InitTypeDef GPIO_opening;
GPIO_PinRemapConfig(GPIO_Remap_SWJ_JTAGDisable ,ENABLE);
/*GPIO_opening.GPIO_Pin = 0xffff;
GPIO_opening.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_opening.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB,&GPIO_opening);
   */
GPIO_opening.GPIO_Pin=GPIO_Pin_7|GPIO_Pin_6;
GPIO_opening.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_opening.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA,&GPIO_opening);

}
#include
void RCC_open(void)
{
// RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);
//RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);
}