STM32按键控制定时器周期
时间: 2023-11-08 18:49:32 浏览: 87
可以使用定时器的输入捕获功能来实现按键控制定时器周期。
具体实现步骤如下:
1. 配置定时器为输入捕获模式,并设置计数器的自动重装载值,这个值决定了定时器的周期。
2. 配置按键引脚为输入模式,并启用中断。
3. 在按键中断处理函数中,读取定时器计数器的值,并根据需要修改自动重装载值,从而改变定时器的周期。
4. 在主函数中启动定时器。
下面是一个示例代码,其中TIM2是定时器,PA0是按键引脚:
```c
#include "stm32f10x.h"
void TIM2_IRQHandler(void)
{
if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET) {
TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
// 读取定时器计数器的值
uint32_t cnt = TIM_GetCapture2(TIM2);
// 根据需要修改自动重装载值
if (cnt > 1000) {
TIM_SetAutoreload(TIM2, 2000);
} else {
TIM_SetAutoreload(TIM2, 1000);
}
}
}
void EXTI0_IRQHandler(void)
{
if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
EXTI_ClearITPendingBit(EXTI_Line0);
// 启动定时器
TIM_Cmd(TIM2, ENABLE);
}
}
int main(void)
{
// 配置定时器
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStruct;
TIM_TimeBaseInitStruct.TIM_Prescaler = 7199; // 72MHz / 7200 = 10kHz
TIM_TimeBaseInitStruct.TIM_Period = 1000; // 默认周期为1s
TIM_TimeBaseInitStruct.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStruct.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseInitStruct);
// 配置定时器输入捕获
TIM_ICInitTypeDef TIM_ICInitStruct;
TIM_ICInitStruct.TIM_Channel = TIM_Channel_2;
TIM_ICInitStruct.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStruct.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStruct.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStruct.TIM_ICFilter = 0;
TIM_ICInit(TIM2, &TIM_ICInitStruct);
// 配置按键引脚
GPIO_InitTypeDef GPIO_InitStruct;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IPU;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStruct);
// 配置中断
NVIC_InitTypeDef NVIC_InitStruct;
NVIC_InitStruct.NVIC_IRQChannel = TIM2_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
NVIC_InitStruct.NVIC_IRQChannel = EXTI0_IRQn;
NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStruct);
EXTI_InitTypeDef EXTI_InitStruct;
EXTI_InitStruct.EXTI_Line = EXTI_Line0;
EXTI_InitStruct.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStruct.EXTI_Trigger = EXTI_Trigger_Rising;
EXTI_InitStruct.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStruct);
// 启动中断
TIM_ITConfig(TIM2, TIM_IT_CC2, ENABLE);
while (1) {
// 主循环
}
return 0;
}
```
在这个示例中,按下按键会启动定时器,定时器周期默认为1s,当定时器计数器的值大于1000时,将定时器周期修改为2s。注意,这里的计数器值和自动重装载值都是按照定时器时钟为10kHz来计算的。