stm32f103c8t6的蜂鸣器引脚为PA0,高电平有效,按键引脚为PA2,低电平为按下,现实现以下功能,按键按下蜂鸣器响,按键松开后蜂鸣器声音慢慢变弱
时间: 2024-06-13 15:08:19 浏览: 40
以下是实现该功能的代码:
```c
#include "stm32f10x.h"
#define BEEP_PIN GPIO_Pin_0
#define BEEP_PORT GPIOA
#define KEY_PIN GPIO_Pin_2
#define KEY_PORT GPIOA
void delay_ms(uint32_t ms)
{
uint32_t i, j;
for (i = 0; i < ms; i++)
for (j = 0; j < 2000; j++);
}
int main(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
GPIO_InitStructure.GPIO_Pin = BEEP_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(BEEP_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = KEY_PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
GPIO_Init(KEY_PORT, &GPIO_InitStructure);
TIM_TimeBaseStructure.TIM_Period = 999;
TIM_TimeBaseStructure.TIM_Prescaler = 71;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
TIM_OCInitStructure.TIM_Pulse = 0;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
TIM_OC1Init(TIM2, &TIM_OCInitStructure);
TIM_Cmd(TIM2, ENABLE);
while (1)
{
if (GPIO_ReadInputDataBit(KEY_PORT, KEY_PIN) == 0)
{
for (int i = 0; i < 1000; i++)
{
TIM_SetCompare1(TIM2, i);
delay_ms(1);
}
}
else
{
for (int i = 1000; i >= 0; i--)
{
TIM_SetCompare1(TIM2, i);
delay_ms(1);
}
}
}
}
```