STM32 用定时器产生1Mhz 脉冲，

STM32 用定时器产生1Mhz 脉冲，PWM宽度可调，四路输出

源码：记得要加入文件 gpio rcc tim 等c文件

include "stm32f10x_conf.h"

void GPIO_CFG(void);
void RCC_CFG(void);
void TIM_CFG(void);
void NVIC_Configuration(void);

int main (void)
{

RCC_CFG();
NVIC_Configuration();
GPIO_CFG();
TIM_CFG();
TIM_Cmd(TIM3,ENABLE);
TIM_CtrlPWMOutputs(TIM3,ENABLE);
//while(1);
}
void RCC_CFG(void)
{
SystemInit();
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_GPIOB,ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
}

void GPIO_CFG(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6|GPIO_Pin_7;
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;
GPIO_Init(GPIOA,&GPIO_InitStructure);
  
GPIO_InitStructure.GPIO_Pin=GPIO_Pin_0|GPIO_Pin_1;
GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;
GPIO_Init(GPIOB,&GPIO_InitStructure);

}
void TIM_CFG(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;

// TIM_Period 计数值，比如  TIM_Period=17   分频参数 TIM_Prescaler=3 （0为不分频），APB1 时钟是72Mhz，

//在本参数情况下， 72Mhz/（17+1）/（3+1）= 1Mhz

// 理论最大频率是 72/(1+1)/1=36Mhz     TIM_Period=1     TIM_Prescaler=0 ,产生的方波可能是三角形的，用模拟示波器才能看出来，数字逻辑分析仪看不错，

// 5Mhz以内的方波应该没问题，如果要产生高频率的方波，感觉应该用SPI的数据时钟来实现

 
TIM_TimeBaseStructure.TIM_Period=17;    //  TIM_Period=70;    TIM_Prescaler=0;    输出1Mhz时钟
TIM_TimeBaseStructure.TIM_Prescaler=3;
TIM_TimeBaseStructure.TIM_ClockDivision=0x00;
TIM_TimeBaseStructure.TIM_CounterMode=TIM_CounterMode_Up;
TIM_TimeBaseStructure.TIM_RepetitionCounter=0x00;
TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);

TIM_OCInitStructure.TIM_OCMode=TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OCPolarity=TIM_OCPolarity_High;
TIM_OCInitStructure.TIM_OutputState=TIM_OutputState_Enable;     
 
// TIM_Pulse的值不可大于TIM_Period
TIM_OCInitStructure.TIM_Pulse=60;      //PA.6
TIM_OC1Init(TIM3,&TIM_OCInitStructure);    


TIM_OCInitStructure.TIM_Pulse=35;   //PA.7
TIM_OC2Init(TIM3,&TIM_OCInitStructure);   

TIM_OCInitStructure.TIM_Pulse=18;   //PB.0
TIM_OC3Init(TIM3,&TIM_OCInitStructure); 

TIM_OCInitStructure.TIM_Pulse=9;   //PB.1
TIM_OC4Init(TIM3,&TIM_OCInitStructure);      

}

//配置中断向量表。决定将程序下载到RAM中还是FLASH中。
void NVIC_Configuration(void)
{

ifdef VECT_TAB_RAM

/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);

else /* VECT_TAB_FLASH */

/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);

endif

}