标题: stm32中断产生ev1527编码 [打印本页]
作者: mylayout 时间: 2019-7-10 14:13
标题: stm32中断产生ev1527编码
利用tim3生成ev1527编码(270K,1200us)
TIM3_PWM_Init(1199,71); //分频后1us,窄脉冲4LCK,宽脉冲12LCK,脉冲周期16LCK;同步周期128LCK(4LCK脉冲，124LCK空白);待生成脉冲周期为1200us
//通过改变TIM3->CCR2的值来改变占空比
#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使能定时器 3时钟
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB|
RCC_APB2Periph_AFIO, ENABLE); //①使能 GPIO 和 AFIO 复用功能时钟
GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3,ENABLE); //②重映射 TIM3_CH2->PB5
//设置该引脚为复用输出功能,输出 TIM3 CH2的 PWM 脉冲波形 GPIOB.5
GPIO_InitStructure.GPIO_Pin =GPIO_Pin_5; //TIM_CH2
GPIO_InitStructure.GPIO_Mode =GPIO_Mode_AF_PP; //复用推挽输出
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; //设置在自动重装载周期值
TIM_TimeBaseStructure.TIM_Prescaler=psc; //设置预分频值
TIM_TimeBaseStructure.TIM_ClockDivision =0; //设置时钟分割:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode =TIM_CounterMode_Up; //TIM 向上计数模式
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; //选择 PWM 模式 1
TIM_OCInitStructure.TIM_OutputState =TIM_OutputState_Enable; //比较输出使能
TIM_OCInitStructure.TIM_OCPolarity =TIM_OCPolarity_High; //输出极性高
TIM_OCInitStructure.TIM_Pulse = 1200;
TIM_OC2Init(TIM3,&TIM_OCInitStructure); //④初始化外设 TIM3 OC2
TIM_OC2PreloadConfig(TIM3,TIM_OCPreload_Enable); //使能预装载寄存器
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) //编码部分
{
if(PULSE_CODE&(1<<(23-pulse_count))) //按位判断PULSE_CODE的二进制从前面开始，如果当前位==1，宽脉冲900，==，窄脉冲300
{
LED0_PWM_DUTY = 900;
pulse_count++;
}
else
{
LED0_PWM_DUTY= 300;
pulse_count++;
}
}
elseif(pulse_count == 24) //同步头
{
LED0_PWM_DUTY= 300;
pulse_count++;
}
elseif(pulse_count<31) //同步低电平部分
{
LED0_PWM_DUTY= 0;
pulse_count++;
}
else
{
LED0_PWM_DUTY= 0;
pulse_count= 0;
}
}
}
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