转一个stm32单一计时器多路捕获PWM信号的方案

地址：http://bbs.5imx3g.com/forum.php?mod=viewthread&tid=70

OP: Ok,I've got it (mostly) worked out thanks to a post here and a post elsewhere. The key is changing polarity of the signal in the IRQ handler. Here,I am assuming that the PWMs are phase aligned,so I only need to check for rising/falling edges of the Channel 1 signal. But this could easily be adapted to allow for PWMs that are not phase-aligned.
Here is my current code,reading 4 PWM signals with a single timer (the ccr[] array holds the current PWM pulse widths):

1. // Hold onto the Channel 1 init structure -- we will use it to reverse
2. // polarity on every edge interrupt.
3. static TIM_ICInitTypeDef TIM_CH1_ICInitStructure;
5. #define GPIO_AF_TIM2 GPIO_AF_2
7. void ConfigPwmIn() {
8. GPIO_InitTypeDef GPIO_InitStructure;
9. TIM_ICInitTypeDef TIM_ICInitStructure;
10. NVIC_InitTypeDef NVIC_InitStructure;
12. TIM_DeInit(TIM2 );
14. /* TIM2 clock enable */
15. RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2,ENABLE);
17. /* GPIOC clock enable */
18. RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOD,ENABLE);
20. /* TIM2 GPIO pin configuration : CH1=PD3,C2=PD4,CH3=PD7,CH4=PD6 */
21. GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3 | GPIO_Pin_4 | GPIO_Pin_7 | GPIO_Pin_6;
22. GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
23. GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
24. GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
25. GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
26. GPIO_Init(GPIOD,&GPIO_InitStructure);
28. /* Connect pins to TIM3 AF2 */
29. GPIO_PinAFConfig(GPIOD,GPIO_PinSource3,GPIO_AF_TIM2 );
30. GPIO_PinAFConfig(GPIOD,GPIO_PinSource4,GPIO_PinSource7,GPIO_PinSource6,GPIO_AF_TIM2 );
32. NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
33. NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
34. NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
35. NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
36. NVIC_Init(&NVIC_InitStructure);
38. /* Enable capture*/
39. TIM_CH1_ICInitStructure.TIM_Channel = TIM_Channel_1;
40. TIM_CH1_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
41. TIM_CH1_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
42. TIM_CH1_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
43. TIM_CH1_ICInitStructure.TIM_ICFilter = 0;
44. TIM_ICInit(TIM2,&TIM_ICInitStructure);
45. TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
46. TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
47. TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
48. TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
49. TIM_ICInitStructure.TIM_ICFilter = 0;
50. TIM_ICInit(TIM2,&TIM_ICInitStructure);
51. TIM_ICInitStructure.TIM_Channel = TIM_Channel_3;
52. TIM_ICInit(TIM2,&TIM_ICInitStructure);
53. TIM_ICInitStructure.TIM_Channel = TIM_Channel_4;
54. TIM_ICInit(TIM2,&TIM_ICInitStructure);
56. /* Enable TIM2 */
57. TIM_Cmd(TIM2,ENABLE);
59. /* Enable CC1-4 interrupt */
60. TIM_ITConfig(TIM2,TIM_IT_CC1 | TIM_IT_CC2 | TIM_IT_CC3 | TIM_IT_CC4,ENABLE);
62. /* Clear CC1 Flag*/
63. TIM_ClearFlag(TIM2,TIM_FLAG_CC1 | TIM_FLAG_CC2 | TIM_FLAG_CC3 | TIM_FLAG_CC4 );
64. }
66. static volatile uint32_t ccr[4];
67. static volatile char pulseState = 0;
69. void TIM2_IRQHandler() {
70. if (TIM2 ->SR & TIM_IT_CC1 ) {
71. TIM2 ->SR &= (~TIM_IT_CC1 );
73. if (pulseState == 0) {
74. TIM_CH1_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
76. // Any time we get a rising edge on CH1,we reset the counter. All channels are
77. // phase aligned,so they all use this as a reference.
78. TIM_SetCounter(TIM2,0);
79. } else {
80. TIM_CH1_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
82. // Pull the value on the falling edge.
83. ccr[0] = TIM_GetCapture1(TIM2 );
84. }
85. pulseState = !pulseState;
87. // Reverse polarity.
88. TIM_ICInit(TIM2,&TIM_CH1_ICInitStructure);
89. }
91. if (TIM2 ->SR & TIM_IT_CC2 ) {
92. TIM2 ->SR &= (~TIM_IT_CC2 );
93. ccr[1] = TIM_GetCapture2(TIM2 );
94. }
95. if (TIM2 ->SR & TIM_IT_CC3 ) {
96. TIM2 ->SR &= (~TIM_IT_CC3 );
97. ccr[2] = TIM_GetCapture3(TIM2 );
98. }
99. if (TIM2 ->SR & TIM_IT_CC4 ) {
100. TIM2 ->SR &= (~TIM_IT_CC4 );
101. ccr[3] = TIM_GetCapture4(TIM2 );
102. }
103. }

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