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標題: stm32中斷產生ev1527編碼 [打印本頁]

作者: mylayout 時間: 2019-7-10 14:13
標題: stm32中斷產生ev1527編碼

利用tim3生成ev1527編碼(270K,1200us)

TIM3_PWM_Init(1199,71); //分頻后1us,窄脈沖4LCK,寬脈沖12LCK,脈沖周期16LCK;同步周期128LCK(4LCK脈沖，124LCK空白);待生成脈沖周期為1200us

//通過改變TIM3->CCR2的值來改變占空比

#define LED0_PWM_DUTY TIM3->CCR2

#define PULSE_CODE 0xD2F672

unsigned int pulse_count=0;

void TIM3_PWM_Init(u16 arr,u16 psc)

{

GPIO_InitTypeDef GPIO_InitStructure;

TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;

TIM_OCInitTypeDef TIM_OCInitStructure;

NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE); //①使能定時器 3時鐘

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|

RCC_APB2Periph_AFIO, ENABLE); //①使能 GPIO 和 AFIO 復用功能時鐘

GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3,ENABLE); //②重映射 TIM3_CH2->PB5

//設置該引腳為復用輸出功能,輸出 TIM3 CH2的 PWM 脈沖波形 GPIOB.5

GPIO_InitStructure.GPIO_Pin =GPIO_Pin_5; //TIM_CH2

GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AF_PP; //復用推挽輸出

GPIO_InitStructure.GPIO_Speed =GPIO_Speed_50MHz;

GPIO_Init(GPIOB,&GPIO_InitStructure); //①初始化 GPIO

//初始化 TIM3

TIM_TimeBaseStructure.TIM_Period =arr; //設置在自動重裝載周期值

TIM_TimeBaseStructure.TIM_Prescaler=psc; //設置預分頻值

TIM_TimeBaseStructure.TIM_ClockDivision =0; //設置時鐘分割:TDTS = Tck_tim

TIM_TimeBaseStructure.TIM_CounterMode =TIM_CounterMode_Up; //TIM 向上計數模式

TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure); //③初始化 TIMx

//初始化 TIM3 Channel2 PWM模式

TIM_OCInitStructure.TIM_OCMode =TIM_OCMode_PWM1; //選擇 PWM 模式 1

TIM_OCInitStructure.TIM_OutputState =TIM_OutputState_Enable; //比較輸出使能

TIM_OCInitStructure.TIM_OCPolarity =TIM_OCPolarity_High; //輸出極性高

TIM_OCInitStructure.TIM_Pulse = 1200;

TIM_OC2Init(TIM3,&TIM_OCInitStructure); //④初始化外設 TIM3 OC2

TIM_OC2PreloadConfig(TIM3,TIM_OCPreload_Enable); //使能預裝載寄存器

NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;

NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;

NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

NVIC_Init(&NVIC_InitStructure);

TIM_ClearFlag(TIM3,TIM_IT_Update);

TIM_ITConfig(TIM3,TIM_IT_Update, ENABLE);

TIM_Cmd(TIM3, ENABLE); //⑤使能 TIM3

}

void TIM3_IRQHandler(void)

{

if(TIM_GetITStatus(TIM3, TIM_IT_Update) == SET)

{

TIM_ClearITPendingBit(TIM3,TIM_IT_Update);

if(pulse_count<24) //編碼部分

{

if(PULSE_CODE&(1<<(23-pulse_count))) //按位判斷PULSE_CODE的二進制從前面開始，如果當前位==1，寬脈沖900，==，窄脈沖300

{

LED0_PWM_DUTY = 900;

pulse_count++;

}

else

{

LED0_PWM_DUTY= 300;

pulse_count++;

}

elseif(pulse_count == 24) //同步頭

{

LED0_PWM_DUTY= 300;

pulse_count++;

}

elseif(pulse_count<31) //同步低電平部分

{

LED0_PWM_DUTY= 0;

pulse_count++;

}

else

{

LED0_PWM_DUTY= 0;

pulse_count= 0;

}

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