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- 2019-9-23
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因项目需要,要做一对200Khz的PWM互补信号,带死区,经过调试发现,用下边的公式计算的时间结果跟示波器实测结果不一样(下图图一):
(图一)
正常输出200KHz互补PWM是这样的:
(图二)
死区配置代码是这样的(因为我自己算的死区时间跟示波器实际测量误差特别大,这里干脆设置为0):
(图三)
做出来的死区是这样的:
(图四)
我想知道:1、为啥死区时间设置为0,还会有死区的延迟效果?(不使用死区初始化函数时没有死区延迟,但是我想知道为什么死区时间设置为0,时仍然会有延迟)
2、我计算的死区时间为什么跟实测会差别那么大?达不到纳秒级别?(我用图一的公式一设定了死区时间,跟公式计算结果误差特别大,最小死区时间只能达到1.5us)
注:时钟频率为168M,分频因子为1。 ( Tds=1s/168M)
附上自己写的代码:
#include "pwm.h"
#include "led.h"
#include "usart.h"
#include "stm32f4xx.h"
#include "stm32f4xx_tim.h"
unsigned char TIM1_UPIT_Flag=0;
//TIM1 PWM2¿·Ö3õê¼»ˉ
//PWMêä3ö3õê¼»ˉ
//arr£o×Ô¶ˉ֨װÖμ
//psc£oê±ÖóÔ¤·ÖÆμêy
void TIM1_PWM_Init(u32 arr,u32 psc)
{
//′Ë2¿·ÖDèêÖ¶ˉDT¸ÄIO¿úéèÖÃ
TIM_BDTRInitTypeDef TIM_BDTRInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1,ENABLE); //TIM1ê±Öóê1Äü
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE,ENABLE); //ê1ÄüPORTEê±Öó
GPIO_PinAFConfig(GPIOE,GPIO_PinSource8,GPIO_AF_TIM1); //GPIOE8¸′óÃÎa¶¨ê±Æ÷1
GPIO_PinAFConfig(GPIOE,GPIO_PinSource9,GPIO_AF_TIM1); //GPIOE9¸′óÃÎa¶¨ê±Æ÷1
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_8|GPIO_Pin_9; //GPIOE8/E9
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //¸′óÃ1|Äü
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; //íÆíì¸′óÃêä3ö
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //2»éÏÏÂà-
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz; //Ëù¶è100MHz
GPIO_Init(GPIOE,&GPIO_InitStructure); //3õê¼»ˉPE8/PE9
TIM_TimeBaseStructure.TIM_Prescaler = psc; //Timer clock = sysclock /(TIM_Prescaler+1) = 168M ¶¨ê±Æ÷·ÖÆμ
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //ÏòéϼÆêyÄ£ê½
TIM_TimeBaseStructure.TIM_Period = arr; //×Ô¶ˉÖØ×°ÔØÖμ
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
TIM_TimeBaseInit(TIM1,&TIM_TimeBaseStructure); //3õê¼»ˉ¶¨ê±Æ÷1
//3õê¼»ˉTIM1 Channel1 PWMÄ£ê½
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1; //Ñ¡Ôñ¶¨ê±Æ÷Ä£ê½:TIMÂö3å¿í¶èμ÷ÖÆÄ£ê½2
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //±è½Ïêä3öê1Äü
TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Enable; //»¥21êä3öÔêDí
TIM_OCInitStructure.TIM_Pulse = (arr+1)/2;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High; //HighÎaÕ¼¿Õ±è¸ß¼«DÔ£¬′Ëê±Õ¼¿Õ±èÎa50%£¬LowÔòÎa·′¼«DÔ£¬Õ¼¿Õ±èÎa50%
TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCPolarity_High; //»¥21êä3ö£¬óëòÔéÏÏà·′
TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCNIdleState_Reset;
// TIM_BDTRInitStructure.TIM_OSSRState = TIM_OSSRState_Enable;
// TIM_BDTRInitStructure.TIM_OSSIState = TIM_OSSIState_Enable;
//TIM_BDTRInitStructure.TIM_LOCKLevel = TIM_LOCKLevel_1;
TIM_BDTRInitStructure.TIM_DeadTime =0x00; //11*1/168M=65ns
// TIM_BDTRInitStructure.TIM_Break = TIM_Break_Enable;
// TIM_BDTRInitStructure.TIM_BreakPolarity = TIM_BreakPolarity_Low; //?PA6???????? PWM????????????
// TIM_BDTRInitStructure.TIM_AutomaticOutput = TIM_AutomaticOutput_Enable;
// TIM_BDTRConfig(TIM1, &TIM_BDTRInitStructure);
TIM_OC1Init(TIM1,&TIM_OCInitStructure); //¸ù¾YTÖ¸¶¨μÄ2Îêy3õê¼»ˉíaéèTIM1OC1
TIM_OC1PreloadConfig(TIM1, TIM_OCPreload_Enable); //ê1ÄüTIM1ÔúCCR1éÏμÄÔ¤×°ÔØ¼Ä′æÆ÷£¨CR×Ô¶ˉ×°ÔØÄ¬èÏêÇ′ò¿aμÄ£©
TIM_ARRPreloadConfig(TIM1,ENABLE);//ARPEê1Äü(ARR×Ô¶ˉ×°ÔØÄ¬èÏêÇ′ò¿aμÄ£¬¿éòÔ2»éèÖÃ)
TIM_Cmd(TIM1,ENABLE);
TIM_CtrlPWMOutputs(TIM1,ENABLE); //ê1ÄüTIM1μÄ WMêä3ö
}
/****************************************************************************************
*? ? ?:bsp_Inittimer1
*????:??????1
*? ?:?
*? ? ?:?
*****************************************************************************************/
void TIM1_IT_Init_DIY(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1,ENABLE);
NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_TIM10_IRQn;/*???1???????*/
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;/*???1???????*/
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;/*?????*/
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;/*?????*/
NVIC_Init(&NVIC_InitStructure);/*??????,?????*/
TIM_ClearFlag(TIM1,TIM_FLAG_Update);/*??????*/
TIM_ITConfig(TIM1,TIM_IT_Update,ENABLE);/*????*/
}
/****************************************************************************************
*? ? ?:TIM1_UP_TIM10_IRQHandler
*????:???1???????
*? ?:?
*? ? ?:?
*****************************************************************************************/
void TIM1_UP_TIM10_IRQHandler(void)
{
// TIM1_UPIT_Flag++;
// if(TIM1_UPIT_Flag==12)
// {
// TIM_Cmd(TIM1,DISABLE);
// TIM1_UPIT_Flag=0;
// }
TIM_ClearFlag(TIM1,TIM_FLAG_Update);
}
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