我用
STM32F103的
timer3输出PWM，在更新中断里通过改变PrescalerValue来频率，但是输出时间有问题啊，在中断里我设置的应该是6s就会点亮（熄灭）一个LED，此LED引脚用于DIR控制，但是实际30多秒才会变。程序比较简单，是个很笨的方法，请前辈们帮帮忙看一下吧，非常感谢了。
main函数的相关程序：
#include "stm32f10x.h"
#include "stm32f10x_tim.h"
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
uint16_t PrescalerValue = 0x1c1f; //预分频值=7200，f=10000
uint16_t cishu=0; //记录中断次数
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
int main(void)
{
/* System Clocks Configuration */
RCC_Configuration();
/* GPIO Configuration */
GPIO_Configuration();
NVIC_Configuration();
TIM_TimeBaseStructure.TIM_Period = 0x0063; //ARR=100 10ms
TIM_TimeBaseStructure.TIM_Prescaler = PrescalerValue;
//TIM_TimeBaseStructure.TIM_Prescaler = 0x1c1f; //预分频值=10000
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0x0; //每次溢出都产生事件更新
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
TIM_ClearFlag(TIM3,TIM_FLAG_Update); //中断标志位清零
TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE); //允许更新中断
/* PWM1 Mode configuration: Channel1 */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 0x0032;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init(TIM3, &TIM_OCInitStructure);
TIM_OC1PreloadConfig(TIM3, TIM_OCPreload_Enable);
TIM_ARRPreloadConfig(TIM3, ENABLE);
/* TIM3 enable counter */
TIM_Cmd(TIM3, ENABLE);
while (1)
{
}
}
void RCC_Configuration(void)
{
/* TIM3 clock enable */
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
/* GPIOA and GPIOB clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOF |
RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
}
void GPIO_Configuration(void)
{
//GPIO_InitTypeDef GPIO_InitStructure;
#ifdef STM32F10X_CL
/*GPIOB Configuration: TIM3 channel1, 2, 3 and 4 */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7 | GPIO_Pin_8 | GPIO_Pin_9;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOC, &GPIO_InitStructure);
GPIO_PinRemapConfig(GPIO_FullRemap_TIM3, ENABLE);
#else
/* GPIOA Configuration:TIM3 Channel1, 2, 3 and 4 as alternate function push-pull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 ; //timer3的ch1输出
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_7; //DIR控制 PF7
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOF, &GPIO_InitStructure);
GPIO_SetBits(GPIOF,GPIO_Pin_7);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; //EN控制 PF6
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOF, &GPIO_InitStructure);
GPIO_SetBits(GPIOF,GPIO_Pin_6);
#endif
}
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn ; //选择定时器TIM3
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0; //选择抢先式优先级（与中断嵌套级别有关）
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1; //选择子优先级（同抢先式优先级的响应顺序）
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //选择使能中断源
NVIC_Init(&NVIC_InitStructure);
}
中断程序如下：
void TIM3_IRQHandler(void)
{
uint16_t i;
i=++cishu;
if ( TIM_GetITStatus(TIM3 , TIM_IT_Update) != RESET ) //自己的程序
{
TIM_ClearITPendingBit(TIM3 , TIM_FLAG_Update);
if(i<50) //f=100,10ms,50次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x1c1f ; //7200
}
else if(49<i&&i<150) //f=200,5ms,100次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x0e0f ; //3600
}
else if(149<i&&i<400) //f=500,2ms,250次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x059f ; //1440
}
else if(399<i&&i<3400) //f=1000,1ms,3000次=3s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x02cf ; //720
}
else if(3399<i&&i<3650) //f=500,2ms,250次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x059f;
}
else if(3649<i&&i<3750) //f=200,5ms,100次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x0e0f;
}
else if(3749<i&&i<3800) //f=100,10ms,50次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x1c1f;
}
else if(3799<i&&i<3850) //反转
{
GPIO_ResetBits(GPIOF,GPIO_Pin_7);
TIM_TimeBaseStructureit.TIM_Prescaler =0x1c1f;
}
else if(3849<i&&i<3950) //f=200,5ms,100次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x0e0f ;
}
else if(3949<i&&i<4200) //f=500,2ms,250次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x059f;
}
else if(4199<i&&i<7200) //f=1000,1ms,3000次=3s
{
TIM_TimeBaseStructureit.TIM_Prescaler = 0x02cf ;
}
else if(7199<i&&i<7450) //f=500,2ms,250次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler =0x059f;
}
else if(7449<i&&i<7550) //f=200,5ms,100次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler =0x0e0f;
}
else if(7549<i&&i<7600) //f=100,10ms,50次=0.5s
{
TIM_TimeBaseStructureit.TIM_Prescaler =0x1c1f;
}
else if(i==7600) //再反转
{
cishu=0;
GPIO_SetBits(GPIOF,GPIO_Pin_7);
TIM_TimeBaseStructureit.TIM_Prescaler =0x1c1f;
}
else {TIM_TimeBaseStructureit.TIM_Prescaler =0x1c1f;}
}
}
最后先谢谢大家了，帮帮忙。
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最后宣布结贴，谢谢大家了，真心的，嘿嘿，以后我也会常来学习并且和大家讨论的。
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