通過串口接收到的數據改變PA8輸出的占空比來控制LED小燈的亮度

主函數

char *str_light = "LIGHT:";

unsigned char PWM_BUF = 0;

int main(void)

{

PWM_Init();

USART3_TIM2_Init(115200);

delay_init();

while(1)

{

if(RX_SATA == 1)

{

if(strstr(RX_BUF,str_light) != 0)

{

delay_ms(1);

PWM_BUF =(RX_BUF[6]-0x30)*10+(RX_BUF[7]-0x30);

TIM_SetCompare1(TIM1,PWM_BUF);

}

RX_SATA = 0;

count = 0;

memset(RX_BUF,0,strlen(RX_BUF));

}

}

}

配置USART3和TIM2

char RX_BUF[20] = {0};

u8 count = 0;

u8 RX_SATA = 0;// 0表示接受未完成 ；1表示接收完成

void USART3_TIM2_Init(u32 bound)

{

NVIC_InitTypeDef NVIC_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

GPIO_InitTypeDef GPIO_InitStructure;

USART_InitTypeDef USART_InitStructure;

//開啟GPIOB 和 復用功能時鐘

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO,ENABLE);

//開啟USART3的時鐘

RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3,ENABLE);

//PB10 ->Tx 配置為復用推挽式輸出 

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;

GPIO_Init(GPIOB, &GPIO_InitStructure);

//PB11 ->Rx 配置為浮空輸入

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;

GPIO_Init(GPIOB, &GPIO_InitStructure);

//配置串口

USART_InitStructure.USART_BaudRate = bound;

USART_InitStructure.USART_WordLength = USART_WordLength_8b;

USART_InitStructure.USART_StopBits = USART_StopBits_1;

USART_InitStructure.USART_Parity = USART_Parity_No;

USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;

USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;

USART_Init(USART3, &USART_InitStructure);

USART_ITConfig(USART3,USART_IT_RXNE,ENABLE);//配置串口接收為中斷模式

NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

USART_Cmd(USART3,ENABLE);

USART_GetFlagStatus(USART3,USART_FLAG_TC);//防止第一個字符被吞

//使能定時器2的時鐘

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);

TIM_TimeBaseStructure.TIM_Period = (100-1);//ARR

TIM_TimeBaseStructure.TIM_Prescaler = (7200-1);//PSC

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM2, & TIM_TimeBaseStructure);

//使能定時器2的中斷

TIM_ITConfig(TIM2,TIM_IT_Update,ENABLE);

//配置定時器2的中斷優先等級

NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

//使能定時器2

TIM_Cmd(TIM2,DISABLE);

}

void USART3_IRQHandler(void)

{

USART_ClearFlag(USART3,USART_FLAG_RXNE);

RX_BUF[count] = USART_ReceiveData(USART3);

count++;

TIM_SetCounter(TIM2,0);

TIM_Cmd(TIM2,ENABLE);

}

void TIM2_IRQHandler(void)

{

TIM_ClearFlag(TIM2,TIM_FLAG_Update);

TIM_Cmd(TIM2,DISABLE);

RX_SATA = 1;

}

配置PWM

void PWM_Init(void)

{

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_OCInitTypeDef TIM_OCInitStructure;

//初始化PA8管腳為復用推挽式輸出

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO,ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //復用推挽式輸出

GPIO_Init(GPIOA, &GPIO_InitStructure);

//初始化定時器1的時基單元

//使能定時器1的時鐘

RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1,ENABLE);

TIM_TimeBaseStructure.TIM_Period = (100-1);//ARR

TIM_TimeBaseStructure.TIM_Prescaler = (72-1);//PSC

TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;

TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;

TIM_TimeBaseInit(TIM1, & TIM_TimeBaseStructure);

//初始化PWM輸出配置

TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;

TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;

TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;

TIM_OCInitStructure.TIM_Pulse = 0;

TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;

TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;

TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;

TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Set;

TIM_OC1Init(TIM1,&TIM_OCInitStructure);

//使能PWM外設

TIM_CtrlPWMOutputs(TIM1,ENABLE);

//激活CCR寄存器

TIM_OC1PreloadConfig(TIM1,TIM_OCPreload_Enable);

//激活ARR寄存器

TIM_ARRPreloadConfig(TIM1,ENABLE);

//使能定時器1

TIM_Cmd(TIM1,ENABLE);

}