蓝桥杯4T平台（频率测量显示）
知识点：输入捕获（单测频率）
题目
配置
代码
uint16_t PR39;
char buf[21];
uint32_t cap; HAL_TIM_IC_Start_IT(&htim3,TIM_CHANNEL_1);void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{
if(htim->Instance==TIM3)
{ cap=HAL_TIM_ReadCapturedValue(&htim3,TIM_CHANNEL_1);
TIM3->CNT=0;
PR39=80000000/80/cap;
HAL_TIM_IC_Start_IT(&htim3,TIM_CHANNEL_1);
}
}void lcd_Proc(void)
{
LCD_DisplayStringLine(Line3,(uint8_t*)" DATA ");
sprintf(buf," PR39:%dHz ",PR39);
LCD_DisplayStringLine(Line4,(uint8_t*)buf);
}