请教定时器外部时钟模式2模式采集脉冲个数的问题

默铭 · 发表于 2018-7-6 10:48:37

请教个问题，我用定时器2的外部时钟模式2检测脉冲个数，用普通IO模拟脉冲波形，然后把这个IO口和定时器2的ETR脚（PA1）短接,定时器2读取到的计数是对的，然后我用定时器3的通道2（PA7）产生PWM波形，把PA7和PA1短接，定时器2计数就不正确了，现象是第一次高电平来的时候，读取到的数值是1，后面再次来高电平时候，数值很大，像是定时器2在高电平期间计数器一直在走。大家有没遇到过这个现象问题
代码如下定时器2的外部模式2初始化代码
I/O口配置下拉和浮空模式都测试过
void TIME1_Init(void)
{

TIM_TimeBaseInitTypeDef TIM1_TimeBaseStructure;
GPIO_InitTypeDef GPIO_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE); //ê1ÄüGPIOíaéèoíAFIO¸′óÃ1|ÄüÄ￡¿éê±Öóê1Äü
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;//GPIO_Mode_IN_FLOATING; //
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M????
GPIO_Init(GPIOA, &GPIO_InitStructure);

TIM_DeInit(TIM2);
TIM1_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM1_TimeBaseStructure.TIM_Prescaler = 0x00;
TIM1_TimeBaseStructure.TIM_ClockDivision = 0x0;
TIM1_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM2, &TIM1_TimeBaseStructure); // Time base configuration

TIM_ETRClockMode2Config(TIM2, TIM_ExtTRGPSC_OFF, TIM_ExtTRGPolarity_NonInverted, 3);
TIM_SetCounter(TIM2, 0);
bcount = 0;
TIM_Cmd(TIM2, ENABLE);
}
这个是读取I/0模拟脉冲的代码
TIME1_Init();
delay_ms(200);
   // GPIO_SetBits(GPIOA,GPIO_Pin_1);    //PA.8 êä3ö¸ß
for(dir = 0;dir<0xfff0;dir++)
{
GPIO_ResetBits(GPIOA,GPIO_Pin_1);
delay_us(5);
GPIO_SetBits(GPIOA,GPIO_Pin_1);
delay_us(5);
}
led0pwmval = TIM_GetCounter(TIM2);

delay_ms(50);
TIM_SetCounter(TIM2, 0);
led0pwmval=0;
for(dir = 0;dir<0xff00;dir++)
{
GPIO_ResetBits(GPIOA,GPIO_Pin_1);
delay_us(1);
GPIO_SetBits(GPIOA,GPIO_Pin_1);
delay_us(1);
}
led0pwmval = TIM_GetCounter(TIM2);

这个是定时器3产生脉冲波，然后在溢出中断里去读取定时器2的计数器
void PWM_Init(u16 arr,u16 psc)
{
NVIC_InitTypeDef NVIC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA  | RCC_APB2Periph_AFIO, ENABLE);  //ê1ÄüGPIOíaéèoíAFIO¸′óÃ1|ÄüÄ￡¿éê±Öóê1Äü
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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);

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GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7; //TIM_CH2
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;  //¸′óÃíÆíìêä3ö
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//GPIO_WriteBit(GPIOA, GPIO_Pin_7,Bit_SET); // PA7éÏà-

TIM_TimeBaseStructure.TIM_Period = arr; //éèÖÃÔúÏÂò»¸ö¸üDÂêÂ¼t×°èë»î¶ˉμÄ×Ô¶ˉÖØ×°ÔØ¼Ä′æÆ÷ÖüÆúμÄÖμ    80K
TIM_TimeBaseStructure.TIM_Prescaler =psc; //éèÖÃóÃà′×÷ÎaTIMxê±ÖóÆμÂê3yêyμÄÔ¤·ÖÆμÖμ  2»·ÖÆμ
TIM_TimeBaseStructure.TIM_ClockDivision = 0; //éèÖÃê±Öó·Ö¸î:TDTS = Tck_tim
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIMÏòéÏ¼ÆêyÄ￡ê½
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure); //¸ù¾YTIM_TimeBaseInitStructÖDÖ¸¶¨μÄ2Îêy3õê¼»ˉTIMxμÄê±¼ä»ùêyμ￥Î»


TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM2; //Ñ¡Ôñ¶¨ê±Æ÷Ä￡ê½:TIMÂö3å¿í¶èμ÷ÖÆÄ￡ê½2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±è½Ïêä3öê1Äü
TIM_OCInitStructure.TIM_Pulse = 0; //éèÖÃ′y×°èë2¶»ñ±è½Ï¼Ä′æÆ÷μÄÂö3åÖμ
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //êä3ö¼«DÔ:TIMêä3ö±è½Ï¼«DÔ¸ß
TIM_OC2Init(TIM3, &TIM_OCInitStructure);  //¸ù¾YTIM_OCInitStructÖDÖ¸¶¨μÄ2Îêy3õê¼»ˉíaéèTIMx
TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Enable);  //ê1ÄüTIMxÔúCCR2éÏμÄÔ¤×°ÔØ¼Ä′æÆ÷

TIM_ARRPreloadConfig(TIM3, ENABLE); //ê1ÄüTIMxÔúARRéÏμÄÔ¤×°ÔØ¼Ä′æÆ÷

NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;  //TIM3ÖD¶Ï
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;  //ÏèÕ¼óÅÏè¼¶0¼¶
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;  //′óóÅÏè¼¶3¼¶
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQí¨μà±»ê1Äü
NVIC_Init(&NVIC_InitStructure);  //¸ù¾YNVIC_InitStructÖDÖ¸¶¨μÄ2Îêy3õê¼»ˉíaéèNVIC¼Ä′æÆ÷

TIM_SetCompare2(TIM3,8);
TIM_SetCounter(TIM3, 0);
TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
acount = 0;
TIM_ITConfig(TIM3,TIM_IT_Update,ENABLE ); //ê1ÄüÖ¸¶¨μÄTIM3ÖD¶Ï,ÔêDí¸üDÂÖD¶Ï
TIM_Cmd(TIM3, ENABLE);  //ê1ÄüTIMxíaéè

}

void TIM3_IRQHandler(void)
{
if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //¼ì2éÖ¸¶¨μÄTIMÖD¶Ï·￠éúóë·ñ:TIM ÖD¶ÏÔ′
{
acount++;
bcount = TIM_GetCounter(TIM2);
TIM_ClearITPendingBit(TIM3, TIM_IT_Update  );  //Çå3yTIMxμÄÖD¶Ï′y′|àíÎ»:TIM ÖD¶ÏÔ′
}
// if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET) //¼ì2éÖ¸¶¨μÄTIMÖD¶Ï·￠éúóë·ñ:TIM ÖD¶ÏÔ′
// {
// bcount = TIM_GetCounter(TIM3);
// TIM_ClearITPendingBit(TIM3, TIM_IT_CC2  );  //Çå3yTIMxμÄÖD¶Ï′y′|àíÎ»:TIM ÖD¶ÏÔ′
// }
}