用定时器主从模式时最后一个脉冲结束时为高电平，怎么让其输出完整的脉冲并最后为低电平？

飞行少年

用定时器的主从模式输出精确脉冲时，最后一个脉冲结束时一直为高电平，等于只输出了半个脉冲，有什么办法可以输出一个完整的脉冲最后为低电平？
仿真如下，输出3个脉冲时


以下为主从模式配置的代码，TIM2为主，TIM3为从

1. void TIM2_Master__TIM3_Slave_Configuration(u32 PulseFrequency)
   
2. {
   
3.         TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
   
4.         TIM_OCInitTypeDef TIM_OCInitStructure;
   
5.        
   
6.         u16 nPDTemp ;
   
7. 
   
8.         TIM_Cmd(TIM2, DISABLE);
   
9.         nPDTemp = 72000UL/PulseFrequency;
   
10.        
    
11.         // TIM2
    
12.         /* Time base configuration */
    
13.         TIM_TimeBaseStructure.TIM_Period = nPDTemp-1;
    
14.         TIM_TimeBaseStructure.TIM_Prescaler = 999;
    
15.         TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    
16.         TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    
17.         TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
    
18.         TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);
    
19.        
    
20.         // TIM2
    
21.         /* PWM1 Mode configuration: Channel1 */   
    
22.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    
23.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    
24.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    
25.         TIM_OCInitStructure.TIM_Pulse = nPDTemp>>1;//50%
    
26.         TIM_OC1Init(TIM2, &TIM_OCInitStructure);
    
27.         TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Enable);
    
28.         TIM_ARRPreloadConfig(TIM2, ENABLE);
    
29. 
    
30.        
    
31.         // TIM3
    
32.         TIM_TimeBaseStructure.TIM_Period = 0xFFFF;                      
    
33.         TIM_TimeBaseStructure.TIM_Prescaler = 0;
    
34.         TIM_TimeBaseStructure.TIM_ClockDivision = 0;
    
35.         TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
    
36.         TIM_TimeBaseStructure.TIM_RepetitionCounter = 0;
    
37.         TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
    
38.        
    
39.         NVIC_InitTypeDef NVIC_InitStructure;
    
40. 
    
41.         NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;                               
    
42.         NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    
43.         NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    
44.         NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    
45.         NVIC_Init(&NVIC_InitStructure);
    
46.        
    
47.         // Output Compare Active Mode configuration: Channel1
    
48.         TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Inactive;
    
49.         TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
    
50.         TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    
51.         TIM_OCInitStructure.TIM_Pulse = 0xFFFF; // ÕâÀïµÄÅäÖÃÖµÒâÒå²»´ó   
    
52.         TIM_OC1Init(TIM3, &TIM_OCInitStructure);
    
53.        
    
54. 
    
55.         // Select the Master Slave Mode
    
56.         TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);
    
57.         // Master Mode selection  
    
58.         TIM_SelectOutputTrigger(TIM2, TIM_TRGOSource_Update);
    
59. 
    
60.         // Slave Mode selection: TIM3
    
61.         TIM_SelectSlaveMode(TIM3, TIM_SlaveMode_Gated);
    
62.         TIM_SelectInputTrigger(TIM3, TIM_TS_ITR1);
    
63.         TIM_ITRxExternalClockConfig(TIM3, TIM_TS_ITR1);
    
64. //        TIM_ITConfig(TIM3, TIM_IT_CC1, ENABLE);                           
    
65.        
    
66.         TIM_Cmd(TIM2, DISABLE);
    
67.         TIM_Cmd(TIM3, DISABLE);
    
68. }
    
69. 
    
70. 
    
71. void Frequence_Setting(u32 PulseFrequency)
    
72. {
    
73.         u16 nPDTemp ;
    
74. 
    
75.         TIM_Cmd(TIM2, DISABLE);
    
76.         nPDTemp = 72000UL/PulseFrequency;
    
77. 
    
78.         TIM_SetAutoreload(TIM2,nPDTemp);
    
79.         TIM_GenerateEvent(TIM2,TIM_EventSource_Update);
    
80.         TIM_SetCompare1(TIM2,nPDTemp/2);
    
81. }
    
82. 
    
83. void Output_Pulse(u16 Num)
    
84. {
    
85.                 TIM_Cmd(TIM3, ENABLE);
    
86.                 TIM3->CCR1 = Num;
    
87.                 TIM3->CNT = 0;
    
88.                 TIM_ITConfig(TIM3, TIM_IT_CC1, ENABLE);
    
89. 
    
90.                 TIM_Cmd(TIM2, ENABLE);
    
91. <div>}</div><div>
    
92. </div><div>void TIM3_IRQHandler(void)
    
93. {
    
94. if (TIM_GetITStatus(TIM3, TIM_IT_CC1) != RESET)     // TIM_IT_CC1
    
95. {
    
96.   TIM_ClearITPendingBit(TIM3, TIM_IT_CC1);
    
97.   TIM_Cmd(TIM2, DISABLE);
    
98.   TIM_ITConfig(TIM3, TIM_IT_CC1, DISABLE);
    
99.   TIM_Cmd(TIM3, DISABLE);
    
100. }
     
101. }
     
102. </div>

复制代码

eric2013

F1的没研究过，H7有研究

借助STM32H7的DMAMUX的定时器触+DMA控制任意IO做PWM和脉冲数控制，爽歪歪
http://www.armbbs.cn/forum.php?m ... 1148&fromuid=58
(出处: 安富莱电子论坛)