请问如何重置PWM

孤独自由死亡 · 发表于 2018-6-8 11:11:37

用PWM实现呼吸灯，希望按下按键可以关闭呼吸灯或者开启呼吸灯，现在开启呼吸灯后会从原来的亮度继续，希望实现的是开启的时候是重新开始的，也就是无论什么时候关闭呼吸灯，开启时都是从不亮慢慢变亮。相关代码如下main.c

[mw_shl_code=c,true]#include "stm32f10x.h"
#include "bsp_breathing.h"
extern uint8_t period_cnt;
extern uint8_t pwm_index;
/**
  * @brief  Ö÷oˉêy
  * @param  ÎT
  * @retval ÎT
  */
int main(void)
{
int flag=1;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;
/* 3õê¼»ˉoôÎüμÆ */

Key_GPIO_Config();

while(1){
if( Key_Scan(GPIOA,GPIO_Pin_0) == 1  )
{
if(flag==1){
TIM3_Breathing_Init();
}else{
TIM_ClearITPendingBit (TIM3, TIM_IT_Update);
period_cnt=0;
pwm_index=0;
TIM3->CCR3=0;
/* PWMÄ￡ê½ÅäÖÃ */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;         //ÅäÖÃÎaPWMÄ￡ê½1
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Disable; //ê1Äüêä3ö
  TIM_OCInitStructure.TIM_Pulse = 0;       //éèÖÃ3õê&#188

WMÂö3å¿í¶èÎa0
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;       //μ±¶¨ê±Æ÷¼ÆêyÖμD¡óúCCR1_Valê±ÎaμíμçÆ½

  TIM_OC3Init(TIM3, &TIM_OCInitStructure);      //ê1Äüí¨μà3
TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Disable); //ê1ÄüÔ¤×°ÔØ

  TIM_ARRPreloadConfig(TIM3, DISABLE);      //ê1ÄüTIM3ÖØÔØ¼Ä′æÆ÷ARR
/* TIM3 enable counter */
  TIM_Cmd(TIM3, DISABLE);                //ê1Äü¶¨ê±Æ÷3

TIM_ITConfig(TIM3,TIM_IT_Update, DISABLE); //ê1ÄüupdateÖD¶Ï

  /* ÅäÖÃoôÎüμÆóÃμ½μ&#196

B0òy½Å */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;       // ¸′óÃíÆíìêä3ö
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOB, &GPIO_InitStructure);

GPIO_SetBits(GPIOB, GPIO_Pin_0);
}
flag=!flag;
}

}
}

/*********************************************END OF FILE**********************/

[/mw_shl_code]

[mw_shl_code=c,true]#include "bsp_breathing.h"

/* LEDáá¶èμè¼¶ PWM±í */
uint8_t indexWave[] = {1,1,2,2,3,4,6,8,10,14,19,25,33,44,59,80,
107,115,143,160,191,255,255,191,160,143,115,107,80,59,44,33,25,19,14,10,8,6,4,3,2,2,1,1};

/**
  * @brief  ÅäÖÃTIM3¸′óÃêä3&#246

WMê±óÃμ½μÄI/O
  * @param  ÎT
  * @retval ÎT
  */
static void TIM3_GPIO_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;

  /* GPIOB clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

  /* ÅäÖÃoôÎüμÆóÃμ½μ&#196

B0òy½Å */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_0 ;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;       // ¸′óÃíÆíìêä3ö
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

  GPIO_Init(GPIOB, &GPIO_InitStructure);
}

/**
  * @brief  ÅäÖÃÇ¶ì×Ïòá¿ÖD¶Ï¿ØÖÆÆ÷NVIC
  * @param  ÎT
  * @retval ÎT
  */
static void NVIC_Config_PWM(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;

  /* Configure one bit for preemption priority */
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

  /* ÅäÖÃTIM3_IRQÖD¶ÏÎaÖD¶ÏÔ′ */
  NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
}

/**
  * @brief  ÅäÖÃTIM3êä3öμ&#196

WMDÅoÅμÄÄ￡ê½￡¬èçÖüÆú¡￠¼«DÔ
  * @param  ÎT
  * @retval ÎT
  */

/*
* TIMxCLK/CK_PSC --> TIMxCNT --> TIMx_ARR --> ÖD¶Ï & TIMxCNT ÖØDÂ¼Æêy
*                   TIMx_CCR(μçÆ½·￠éú±ä»ˉ)
*
* DÅoÅÖüÆú=(TIMx_ARR +1 ) * ê±ÖóÖüÆú
*
*/

/* _______ ______    _____    ____    ___       __       _
* |_|    |__|    |___|    |____| |_____| |______|  |_______| |________|
*/
static void TIM3_Mode_Config(void)
{
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_OCInitTypeDef  TIM_OCInitStructure;

/* éèÖÃTIM3CLK ê±ÖóÎa72MHZ */
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE); //ê1ÄüTIM3ê±Öó

  /* »ù±¾¶¨ê±Æ÷ÅäÖÃ */
  TIM_TimeBaseStructure.TIM_Period = 255;       //μ±¶¨ê±Æ÷′ó0¼Æêyμ½255￡¬¼′Îa266′Î￡¬Îaò»¸ö¶¨ê±ÖüÆú
  TIM_TimeBaseStructure.TIM_Prescaler = 1999;         //éèÖÃÔ¤·ÖÆμ￡o
  TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1 ; //éèÖÃê±Öó·ÖÆμÏμêy￡o2»·ÖÆμ(ÕaàïóÃ2»μ½)
  TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;    //ÏòéÏ¼ÆêyÄ￡ê½
  TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

  /* PWMÄ￡ê½ÅäÖÃ */
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;         //ÅäÖÃÎaPWMÄ￡ê½1
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //ê1Äüêä3ö
  TIM_OCInitStructure.TIM_Pulse = 0;       //éèÖÃ3õê&#188

WMÂö3å¿í¶èÎa0
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low;       //μ±¶¨ê±Æ÷¼ÆêyÖμD¡óúCCR1_Valê±ÎaμíμçÆ½

  TIM_OC3Init(TIM3, &TIM_OCInitStructure);      //ê1Äüí¨μà3

  TIM_OC3PreloadConfig(TIM3, TIM_OCPreload_Enable); //ê1ÄüÔ¤×°ÔØ

  TIM_ARRPreloadConfig(TIM3, ENABLE);      //ê1ÄüTIM3ÖØÔØ¼Ä′æÆ÷ARR

  /* TIM3 enable counter */
  TIM_Cmd(TIM3, ENABLE);                //ê1Äü¶¨ê±Æ÷3

TIM_ITConfig(TIM3,TIM_IT_Update, ENABLE); //ê1ÄüupdateÖD¶Ï

NVIC_Config_PWM(); //ÅäÖÃÖD¶ÏóÅÏè¼¶

}

/**
  * @brief  TIM3 oôÎüμÆ3õê¼»ˉ
  *       ÅäÖ&#195

WMÄ￡ê½oíGPIO
  * @param  ÎT
  * @retval ÎT
  */
void TIM3_Breathing_Init(void)
{
TIM3_GPIO_Config();
TIM3_Mode_Config();
}

void Key_GPIO_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;

/*¿aÆô°′¼ü¶Ë¿ú￡¨PA￡©μÄê±Öó*/
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;

// IO ¿ú×öêäèë¿úê±￡¬2»óÃéèÖÃêä3öÆμÂê
//GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;

GPIO_Init(GPIOA, &GPIO_InitStructure);
}

uint8_t Key_Scan(GPIO_TypeDef* GPIOx,uint16_t GPIO_Pin)
{
/*¼ì2aêÇ·ñóD°′¼ü°′ÏÂ */
if(GPIO_ReadInputDataBit(GPIOx,GPIO_Pin) == 1 )
{
/*μè′y°′¼üêí·Å */
while(GPIO_ReadInputDataBit(GPIOx,GPIO_Pin) == 1);
return 1;
}
else
return 0;
}

/*********************************************END OF FILE**********************/
[/mw_shl_code]
中断服务函数
[mw_shl_code=c,true]void TIM3_IRQHandler(void)
{

if (TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET) //TIM_IT_Update
{
period_cnt++;
if(period_cnt >= 10) //èôêä3öμÄÖüÆúêy′óóú10￡¬êä3öÏÂò»ÖÖÂö3å¿íμ&#196

WM2¨
{

TIM3->CCR3 = indexWave[pwm_index]; //¸ù¾YPWM±íDT¸Ä¶¨ê±Æ÷μÄ±è½Ï¼Ä′æÆ÷Öμ
pwm_index++; //±êÖ&#190

WM±íμÄÏÂò»¸öÔaËØ

if( pwm_index >= 44) //è&#244

WMÂö3å±íòÑ¾-êä3öíê3éò»±é￡¬ÖØÖÃPWM2é±í±êÖ¾
{
pwm_index=0;
}

period_cnt=0; //ÖØÖÃÖüÆú¼Æêy±êÖ¾
}
TIM_ClearITPendingBit (TIM3, TIM_IT_Update); //±ØDëòaÇå3yÖD¶Ï±êÖ¾Î»
}
}[/mw_shl_code]