C
#include "stm32f10x.h"
#include "sys.h"
static GPIO_InitTypeDef GPIO_InitStructure;
static TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;//配置频率
static TIM_OCInitTypeDef TIM_OCInitStructure; //配置占空比
static uint32_t temp=0;
#define PB8OUT(n) *(volatile uint32_t *)(0x42000000+((uint32_t)&GPIOB->ODR-0x40000000)*32+n*4)
void delay_ms(uint32_t n){
while(n--){
SysTick->CTRL=0; //关闭系统定时器,第0位:使能位,1为使能
SysTick->LOAD=(72000)-1;//配置计数值,因为计算机从0开始,所以减一
SysTick->VAL=0;//清空当前的值(标志位),定时器在计数时,标志位为0,当计数完毕时,标志位为1
SysTick->CTRL=5;//5=101 使能系统计时器,并且使用系统时钟
//第二位:时钟选择位,0=系统时钟/8,1=系统时钟
while((SysTick->CTRL&0x10000)==0);//等待计数到0
//第16位:计数到0则为1
}
SysTick->CTRL=0;
}
void BEEPinit(void){
//蜂鸣器PB8/TIM4_CH3
//使能端口
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
//初始化GPIO引脚
GPIO_InitStructure.GPIO_Pin=GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;//要用到复用功能,所以把引脚的模式改成复用推挽
GPIO_InitStructure.GPIO_Speed= GPIO_Speed_50MHz;//高速响应
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_ResetBits(GPIOB,GPIO_Pin_8);
}
//设置频率
void TIM4init(uint32_t frep){
// 蜂鸣器PB8/TIM4_CH3
//使能定时器4硬件时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
TIM_TimeBaseStructure.TIM_Period = 10000/frep-1;//计数值,决定输出频率为100Hz
TIM_TimeBaseStructure.TIM_Prescaler = 7200-1;//预分频器7100-1+1,隐形着一个+1操作,所以要减一
TIM_TimeBaseStructure.TIM_ClockDivision = 0;//这个用不到
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;//向上计数
TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);
temp=TIM_TimeBaseStructure.TIM_Period;
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //通道
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //打开/关闭脉冲输出
TIM_OCInitStructure.TIM_Pulse = 0; //比较值
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //输出电平的极性,有效状态为高电平,则无效状态是低电平
TIM_OC3Init(TIM4, &TIM_OCInitStructure);
TIM_Cmd(TIM4, ENABLE);
}
//设置占空比
void TIM4_setduty(uint16_t duty){
uint16_t compare=0;
compare=(temp+1)*duty/100;//(计数值+1)*占空比
TIM_SetCompare3(TIM4,compare);//由通道决定是几,CH3所以就选Compare3;
}
int main(){
uint32_t i;
uint16_t frep[10]={262,1976,784,494,330,698};
BEEPinit();
while(1){
for(i=0;i<10;i++){
TIM4init(frep[i]);
TIM4_setduty(50);
delay_ms(1000);
}
}
}

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