基于stm32F4的频率计程序 -

#include "stm32f4xx.h"
#include "delay.h"
#include "usart.h"
#include "counter.h"
//#include "SysTick.h"
#include "sys.h"
#include "stdio.h"
/***********************************************************************************************
定时器外部时钟模式
************************************************************************************************/
u32 count_s;
u16 count_ms;
extern u16 count_i;
extern u16 count_over;
int main(void)
{
NVIC_Configuration(); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
uart_init(9600); //串口初始化为9600
TIM3_External_Clock_CountingMode();
TIM4_timer_Init();
while(1)
{
if(count_i>100)
{
count_ms = TIM3->CNT;
count_s = count_over*65535.0 + count_ms;
printf("%.3f kHz\r\n ",count_s/1000.0); //打印数据
count_i=0;
count_over=0;
TIM3->CNT=0;
}
}
}

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