怎么用STM32配置产生PWM（一个定时器用输出比较方式产生不同频率的PWM）

STM32产生PWM是非常的方便的，要需要简单的设置定时器，即刻产生！当然，简单的设置对于新手来讲，也是麻烦的，主要包括： （1）使能定时器时钟：

1. RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

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（2）定义相应的GPIO：

1. /* PA2,3,4,5,6输出->Key_Up,Key_Down,Key_Left,Key_Right,Key_Ctrl */
   
2. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6;
   
3. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //下拉接地，检测输入的高电平
   
4. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
   
5. GPIO_Init(GPIOA, &GPIO_InitStructure);
   
6. /* PA7用于发出PWM波,即无线数据传送 */
   
7. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_7;
   
8. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; 
   
9. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
   
10. GPIO_Init(GPIOA, &GPIO_InitStructure);

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（3）如果是产生PWM（频率不变，占空比可变），记得打开PWM控制，在TIM_Configuration()中。

1. TIM_Cmd(TIM3,ENABLE);
   
2. 
   
3. /* TIM1 Main Output Enable */
   
4. TIM_CtrlPWMOutputs(TIM1,ENABLE);

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利用定时器产生不同频率的PWM 有时候，需要产生不同频率的PWM，这个时候，设置与产生相同PWM的程序，有关键的不一样。 （一） 设置的原理 利用改变定时器输出比较通道的捕获值，当输出通道捕获值产生中断时，在中断中将捕获值改变，这时， 输出的I/O会产生一个电平翻转，利用这种办法，实现不同频率的PWM输出。 （二）关键设置 在定时器设置中：

1. TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);

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在中断函数中：

1. if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
   
2. {
   
3. TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
   
4. capture = TIM_GetCapture2(TIM3);
   
5. TIM_SetCompare2(TIM3, capture + Key_Value);
   
6. }

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一个定时器四个通道，分别产生不同频率（这个例子网上也有）

1. vu16 CCR1_Val = 32768;
   
2. vu16 CCR2_Val = 16384;
   
3. vu16 CCR3_Val = 8192;
   
4. vu16 CCR4_Val = 4096;
5. void TIM_Configuration(void)
   
6. {
   
7.   TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
   
8.   TIM_OCInitTypeDef TIM_OCInitStructure;
   
9.   /* TIM2 clock enable */
   
10.   RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
    
11.   /* ---------------------------------------------------------------
    
12.   TIM2 Configuration: Output Compare Toggle Mode:
    
13.   TIM2CLK = 36 MHz, Prescaler = 0x2, TIM2 counter clock = 12 MHz 
    
14.   CC1 update rate = TIM2 counter clock / CCR1_Val = 366.2 Hz
    
15.   CC2 update rate = TIM2 counter clock / CCR2_Val = 732.4 Hz 
    
16.   CC3 update rate = TIM2 counter clock / CCR3_Val = 1464.8 Hz 
    
17.   CC4 update rate = TIM2 counter clock / CCR4_Val = 2929.6 Hz 
    
18.   --------------------------------------------------------------- *//* Time base configuration */
    
19.   TIM_TimeBaseStructure.TIM_Period = 65535; 
    
20.   TIM_TimeBaseStructure.TIM_Prescaler = 2; 
    
21.   TIM_TimeBaseStructure.TIM_ClockDivision = 0; 
    
22.   TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; 
    
23. 
    
24.   TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure);/* Channel 1 Configuration in PWM mode */
    
25.   TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM模式2
    
26.   TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
    
27.   TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效
    
28.   TIM_OCInitStructure.TIM_Pulse = CCR1_Val; //占空时间
    
29.   TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
    
30.   TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High; //互补端的极性 
    
31.   TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
    
32.   TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;TIM_OC1Init(TIM2,&TIM_OCInitStructure); //通道1
    
33.   TIM_OC1PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR2_Val; //占空时间
    
34.   TIM_OC2Init(TIM2,&TIM_OCInitStructure); //通道2
    
35.   TIM_OC2PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR3_Val; //占空时间
    
36.   TIM_OC3Init(TIM2,&TIM_OCInitStructure); //通道3
    
37.   TIM_OC3PreloadConfig(TIM2, TIM_OCPreload_Disable);TIM_OCInitStructure.TIM_Pulse = CCR4_Val; //占空时间
    
38.   TIM_OC4Init(TIM2,&TIM_OCInitStructure); //通道4
    
39.   TIM_OC4PreloadConfig(TIM2, TIM_OCPreload_Disable);
    
40.   /* TIM2 counter enable */
    
41.   TIM_Cmd(TIM2,ENABLE);
    
42. 
    
43.   /* TIM2 Main Output Enable */
    
44.   //TIM_CtrlPWMOutputs(TIM2,ENABLE);/* TIM IT enable */
45.   TIM_ITConfig(TIM2, TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4, ENABLE);
46. }
47. void GPIO_Configuration(void)
    
48. {
    
49.   GPIO_InitTypeDef GPIO_InitStructure;/*允许总线CLOCK,在使用GPIO之前必须允许相应端的时钟.从STM32的设计角度上说,没被允许的端将不接入时钟,也就不会耗能,这是STM32节能的一种技巧,*/
50. 
    
51. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    
52. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
    
53. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC, ENABLE);
    
54. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD, ENABLE);
    
55. 
    
56. /* PA2,3,4,5,6,7输出->LED1,LED2,LED3,LED4,LED5,LED6 */
    
57. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4|GPIO_Pin_5|GPIO_Pin_6|GPIO_Pin_7;
    
58. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出
    
59. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
    
60. GPIO_Init(GPIOA, &GPIO_InitStructure);
    
61. 
    
62. /* PB0,1输出->LED7,LED8*/
    
63. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
    
64. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_OD; //开漏输出
    
65. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; //50M时钟速度
    
66. GPIO_Init(GPIOB, &GPIO_InitStructure);
    
67. 
    
68. /* PA0,1->KEY_LEFT,KEY_RIGHT*/
    
69. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1;
    
70. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉输入
    
71. GPIO_Init(GPIOA, &GPIO_InitStructure);/* PC13->KEY_UP*/
    
72. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
    
73. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉输入
    
74. GPIO_Init(GPIOC, &GPIO_InitStructure);/* PB5->KEY_DOWN*/
    
75. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
    
76. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //上拉输入
    
77. GPIO_Init(GPIOB, &GPIO_InitStructure);
78. /* GPIOA Configuration:TIM2 Channel1, 2, 3 and 4 in Output */
    
79. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 | GPIO_Pin_3;
    
80. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    
81. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
82. GPIO_Init(GPIOA, &GPIO_InitStructure);
    
83. }
84. void NVIC_Configuration(void)
    
85. {
    
86. NVIC_InitTypeDef NVIC_InitStructure;/* Configure one bit for preemption priority */
    
87. NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);NVIC_InitStructure.NVIC_IRQChannel=TIM2_IRQn;
    
88. NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
    
89. NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
    
90. NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
    
91. NVIC_Init(&NVIC_InitStructure);
    
92. }
93. 
    
94. u16 capture = 0;
    
95. extern vu16 CCR1_Val;
    
96. extern vu16 CCR2_Val;
    
97. extern vu16 CCR3_Val;
    
98. extern vu16 CCR4_Val;
99. 
    
100. void TIM2_IRQHandler(void)
     
101. {
102. /* TIM2_CH1 toggling with frequency = 183.1 Hz */
     
103. if (TIM_GetITStatus(TIM2, TIM_IT_CC1) != RESET)
     
104. {
     
105. TIM_ClearITPendingBit(TIM2, TIM_IT_CC1 );
     
106. capture = TIM_GetCapture1(TIM2);
     
107. TIM_SetCompare1(TIM2, capture + CCR1_Val );
     
108. }
     
109. 
     
110. /* TIM2_CH2 toggling with frequency = 366.2 Hz */
     
111. if (TIM_GetITStatus(TIM2, TIM_IT_CC2) != RESET)
     
112. {
     
113. TIM_ClearITPendingBit(TIM2, TIM_IT_CC2);
     
114. capture = TIM_GetCapture2(TIM2);
     
115. TIM_SetCompare2(TIM2, capture + CCR2_Val);
     
116. }/* TIM2_CH3 toggling with frequency = 732.4 Hz */
     
117. if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET)
     
118. {
     
119. TIM_ClearITPendingBit(TIM2, TIM_IT_CC3);
     
120. capture = TIM_GetCapture3(TIM2);
     
121. TIM_SetCompare3(TIM2, capture + CCR3_Val);
     
122. }/* TIM2_CH4 toggling with frequency = 1464.8 Hz */
     
123. if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET) 
     
124. {
     
125. TIM_ClearITPendingBit(TIM2, TIM_IT_CC4);
     
126. capture = TIM_GetCapture4(TIM2);
     
127. TIM_SetCompare4(TIM2, capture + CCR4_Val);
     
128. }}

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一个定时器一个通道，产生不同频率 其它的设置都一样，就是在主函数中修改一个参数，然后在定时器中断中，根据这个参数，改变频率。

1. #include "stm32lib\\stm32f10x.h"
   
2. #include "hal.h"volatile u16 Key_Value=1000; //用于保存按键相应的PWM波占空比值
   
3. int main(void)
   
4. {
   
5. ChipHalInit();
   
6. ChipOutHalInit();while(1)
   
7. { 
   
8. if( (!Get_Key_Up)&(!Get_Key_Down)&(!Get_Key_Left)&(!Get_Key_Right)&(!Get_Key_Ctrl) )
   
9. {
   
10. Key_Value=12000;
    
11. }
    
12. else 
    
13. {
    
14. if(Get_Key_Up) //按键前进按下 ,对应1kHz
    
15. {
    
16. Key_Value=6000;
    
17. }
    
18. else if(Get_Key_Down) //按键后退按下 ,对应2kHz
    
19. {
    
20. Key_Value=3000;
    
21. }
    
22. Delay_Ms(20); //10ms延时if(Get_Key_Left) //按键左转按下,对应3kHz
    
23. {
    
24. Key_Value=2000;
    
25. }
    
26. else if(Get_Key_Right) //按键右转按下,对应4kHz
    
27. {
    
28. Key_Value=1500;
    
29. } 
    
30. Delay_Ms(20); //10ms延时if(Get_Key_Ctrl) //按键控制按下,对应5kHz
    
31. {
    
32. Key_Value=1200;
    
33. }
    
34. Delay_Ms(20); //10ms延时 
    
35. }
    
36. }
    
37. }extern volatile u16 Key_Value;
    
38. u16 capture=0;
    
39. void TIM3_IRQHandler(void)
    
40. {
    
41. /* TIM2_CH2 toggling with frequency = 366.2 Hz */
    
42. if (TIM_GetITStatus(TIM3, TIM_IT_CC2) != RESET)
    
43. {
    
44. TIM_ClearITPendingBit(TIM3, TIM_IT_CC2);
    
45. capture = TIM_GetCapture2(TIM3);
    
46. TIM_SetCompare2(TIM3, capture + Key_Value);
    
47. } 
    
48. }void TIM3_Configuration(void)
    
49. {
    
50. TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    
51. TIM_OCInitTypeDef TIM_OCInitStructure;/* TIM2 clock enable */
    
52. RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);/*TIM1时钟配置*/
    
53. TIM_TimeBaseStructure.TIM_Prescaler = 5; //预分频(时钟分频)72M/6=12M
    
54. TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up; //向上计数
    
55. TIM_TimeBaseStructure.TIM_Period = 65535; //装载值选择最大
    
56. TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    
57. TIM_TimeBaseStructure.TIM_RepetitionCounter = 0x0;
    
58. TIM_TimeBaseInit(TIM3,&TIM_TimeBaseStructure);/* Channel 1 Configuration in PWM mode */
    
59. TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_Toggle; //PWM模式2
    
60. TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable; //正向通道有效
    
61. TIM_OCInitStructure.TIM_OutputNState = TIM_OutputNState_Disable;//反向通道无效
    
62. TIM_OCInitStructure.TIM_Pulse = Key_Value; //占空时间
    
63. TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; //输出极性
    
64. TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_High; //互补端的极性 
    
65. TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Set;
    
66. TIM_OCInitStructure.TIM_OCNIdleState = TIM_OCIdleState_Reset;TIM_OC2Init(TIM3,&TIM_OCInitStructure); //通道2
    
67. TIM_OC2PreloadConfig(TIM3, TIM_OCPreload_Disable);
    
68. 
    
69. /* TIM1 counter enable */
    
70. TIM_Cmd(TIM3,ENABLE);
    
71. 
    
72. /* TIM1 Main Output Enable */
    
73. //TIM_CtrlPWMOutputs(TIM1,ENABLE); 
    
74. TIM_ITConfig(TIM3, TIM_IT_CC2 , ENABLE); 
    
75. }

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注意：在计算PWM频率的时候，TIMx的时钟都是72Mhz，分频后，因为翻转两次才能形成一个PWM波，因为，PWM的频率是捕获改变频率的1/2。