1输入捕获作为定时器的一个功能.docx

输入捕获作为定时器的一个功能，在工业测速上有很大的应用。STM32的一些定时器具有四个外部通道，可利用一个定时器采集外部四路脉冲频率，节约硬件资源和软件代码如需要测量一个或多个外部方波脉冲频率，频率低于单片机运行频率，可如下操作：（以TIM4为例）初始化：(省略GPIO配置，将TIM4的四个通道引脚配置为上拉或浮空输入，省略定时器RCC配置，省略中断NVIC配置)1.2. void TIM_Configuration(void)3. 4. 5. TIM_ICInitTypeDef6. TIM_ICInitStructure;7. TIM_TimeBaseInitTypeDef8. TIM_TimeBaseStructure; / TIM4 时基9. 10. TIM_DeInit(TIM4);11. TIM_TimeBaseStructure.TIM_Period =12. 0xffff; 13. /自动重装值14. TIM_TimeBaseStructure.TIM_Prescaler =15. 719; 16. /预分频值, 使TIMx_CLK=100K=10us17. 18. TIM_TimeBaseStructure.TIM_ClockDivision =19. TIM_CKD_DIV1; 20. /输入时钟不分频21. TIM_TimeBaseStructure.TIM_CounterMode =22. TIM_CounterMode_Up; 23. /向上计数24. TIM_TimeBaseInit(TIM4,25. &TIM_TimeBaseStructure);26. 27. /TIM4_TimeBase28. /TIM_ICInitStructure.TIM_ICMode =29. TIM_ICMode_ICAP; 30. /输入捕捉方式31. TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;/|32. TIM_Channel_2; /输入通道33. 34. TIM_ICInitStructure.TIM_ICPolarity =35. TIM_ICPolarity_Rising; /捕捉上升沿36. 37. TIM_ICInitStructure.TIM_ICSelection =38. TIM_ICSelection_DirectTI; /捕捉中断39. 40. TIM_ICInitStructure.TIM_ICPrescaler =41. TIM_ICPSC_DIV1; /捕捉不分频42. 43. TIM_ICInitStructure.TIM_ICFilter =44. 0x0; /捕捉输入不滤波45. TIM_ICInit(TIM4, &TIM_ICInitStructure);46. TIM_ICInitStructure.TIM_Channel = TIM_Channel_2 ;/|47. TIM_Channel_2; /输入通道48. 49. TIM_ICInitStructure.TIM_ICPolarity =50. TIM_ICPolarity_Rising; /捕捉上升沿51. 52. TIM_ICInitStructure.TIM_ICSelection =53. TIM_ICSelection_DirectTI; /捕捉中断54. 55. TIM_ICInitStructure.TIM_ICPrescaler =56. TIM_ICPSC_DIV1; /捕捉不分频57. 58. TIM_ICInitStructure.TIM_ICFilter =59. 0x0; /捕捉输入不滤波60. TIM_ICInit(TIM4, &TIM_ICInitStructure);61. TIM_ICInitStructure.TIM_Channel = TIM_Channel_3 ;/|62. TIM_Channel_2; /输入通道63. 64. TIM_ICInitStructure.TIM_ICPolarity =65. TIM_ICPolarity_Rising; /捕捉上升沿66. 67. TIM_ICInitStructure.TIM_ICSelection =68. TIM_ICSelection_DirectTI; /捕捉中断69. 70. TIM_ICInitStructure.TIM_ICPrescaler =71. TIM_ICPSC_DIV1; /捕捉不分频72. 73. TIM_ICInitStructure.TIM_ICFilter =74. 0x0; /捕捉输入不滤波75. TIM_ICInit(TIM4, &TIM_ICInitStructure);76. TIM_ICInitStructure.TIM_Channel = TIM_Channel_4 ;/|77. TIM_Channel_2; /输入通道78. 79. TIM_ICInitStructure.TIM_ICPolarity =80. TIM_ICPolarity_Rising; /捕捉上升沿81. 82. TIM_ICInitStructure.TIM_ICSelection =83. TIM_ICSelection_DirectTI; /捕捉中断84. 85. TIM_ICInitStructure.TIM_ICPrescaler =86. TIM_ICPSC_DIV1; /捕捉不分频87. 88. TIM_ICInitStructure.TIM_ICFilter =89. 0x0; /捕捉输入不滤波90. TIM_ICInit(TIM4, &TIM_ICInitStructure);91. /* TIM enable counter */92. TIM_Cmd(TIM4, ENABLE);93. /* Enable the CC2 Interrupt Request */94. TIM_ITConfig(TIM4,95. TIM_IT_CC1, ENABLE);96. TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE);97. 98. TIM_ITConfig(TIM4, TIM_IT_CC3, ENABLE);99. TIM_ITConfig(TIM4, TIM_IT_CC4,100. ENABLE);101. 复制代码其中：TIM_TimeBaseStructure.TIM_Period = 0xffff;为自动重装值，与普通单片机一样TIM_TimeBaseStructure.TIM_Prescaler = 719; 预分频值, 使TIMx_CLK=100KHz ，系统时钟运行于72M时720分频，定时器运行于100KHZ，即10us每分度捕获一次TIM_ICInitStructure.TIM_ICMode = TIM_ICMode_ICAP; 此句选择定时器为输入捕获模式，但在我的库函数下未定义，所以注释掉，未影响程序执行TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;配置通道1TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;上升沿捕获TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;捕获中断TIM_ICInitStructure.TIM_ICFilter = 0x0;不滤波TIM_ICInit(TIM4, &TIM_ICInitStructure);将配置应用以上每个通道都需要将整个配置再写一遍，使用与|是无效的。TIM_Cmd(TIM4, ENABLE);使能定时器4TIM_ITConfig(TIM4, TIM_IT_CC1, ENABLE);TIM_ITConfig(TIM4, TIM_IT_CC2, ENABLE);TIM_ITConfig(TIM4, TIM_IT_CC3, ENABLE);TIM_ITConfig(TIM4, TIM_IT_CC4, ENABLE);打开四个通道的捕获中断以上将TIM配置完成，下面是中断内代码：1.2. void3. TIM4_IRQHandler(void)4. 5. 6. /频率缓冲区计数7. static u16 this_time_CH1 = 0;8. static u169. last_time_CH1 = 0;10. static u8 capture_number_CH1 = 0;11. vu1612. tmp16_CH1;13. static u16 this_time_CH2 = 0;14. static u16 last_time_CH2 = 0;15.16. static u8 capture_number_CH2 = 0;17. vu16 tmp16_CH2;18. static u16 this_time_CH3 = 0;19. static u16 last_time_CH3 = 0;20.21. static u8 capture_number_CH3 = 0;22. vu16 tmp16_CH3;23. static u16 this_time_CH4 = 0;24. static u16 last_time_CH4 = 0;25.26. static u8 capture_number_CH4 = 0;27. vu16 tmp16_CH4;28.29. if(TIM_GetITStatus(TIM4, TIM_IT_CC1) = SET)30.31. 32. 33. TIM_ClearITPendingBit(TIM4, TIM_IT_CC1);34. if(capture_number_CH1 = 0)35.36. 37.38. 39. capture_number_CH1 = 1;40.41. 42. last_time_CH1 = TIM_GetCapture1(TIM4);43.44. 45.46. else if(capture_number_CH1 = 1)47.48. 49.50. 51. capture_number_CH1 = 0;52.53. 54. this_time_CH1 = TIM_GetCapture1(TIM4);55. 56. if(this_time_CH1 last_time_CH1)57.58. 59.60. 61. tmp16_CH1 = (this_time_CH1 - last_time_CH1);62.63. 64.65. else66.67. 68.69. 70. tmp16_CH1 = (0xFFFF - last_time_CH1) + this_time_CH1);71.72. 73. /TIM274. counter clock = 1MHz75.76. / 77. FreqBufcnt = (1000000L * 100) /78. tmp16; 79. /*100为扩大显示量程80. Freq_Value0=tmp16_CH1;81.82. 83. 84. if(TIM_GetITStatus(TIM4, TIM_IT_CC2) = SET)85.86. 87. 88. TIM_ClearITPendingBit(TIM4, TIM_IT_CC2);89. if(capture_number_CH2 = 0)90.91. 92.93. 94. capture_number_CH2 = 1;95.96. 97. last_time_CH2 = TIM_GetCapture2(TIM4);98.99. 100.101. else if(capture_number_CH2 = 1)102.103. 104.105. 106. capture_number_CH2 = 0;107.108. 109. this_time_CH2 = TIM_GetCapture2(TIM4);110. 111. if(this_time_CH2 last_time_CH2)112.113. 114.115. 116. tmp16_CH2 = (this_time_CH2 - last_time_CH2);117.118. 119.120. else121.122. 123.124. 125. tmp16_CH2 = (0xFFFF - last_time_CH2) + this_time_CH2);126.127. 128. /TIM2129. counter clock = 1MHz130.131. / 132. FreqBufcnt = (1000000L * 100) /133. tmp16; 134. /*100为扩大显示量程135. Freq_Value1=tmp16_CH2;136.137. 138. 139. 140.141. if(TIM_GetITStatus(TIM4, TIM_IT_CC3) = SET)142.143. 144. 145. TIM_ClearITPendingBit(TIM4, TIM_IT_CC3);146. if(capture_number_CH3 = 0)147.148. 149.150. 151. capture_number_CH3 = 1;152.153. 154. last_time_CH3 = TIM_GetCapture3(TIM4);155.156. 157.158. else if(capture_number_CH3 = 1)159.160. 161.162. 163. capture_number_CH3 = 0;164.165. 166. this_time_CH3 = TIM_GetCapture3(TIM4);167. 168. if(this_time_CH3 last_time_CH3)169.170. 171.172. 173. tmp16_CH3 = (this_time_CH3 - last_time_CH3);174.175. 176.177. else178.179. 180.181. 182. tmp16_CH3 = (0xFFFF - last_time_CH3) + this_time_CH3);183.184. 185. /TIM2186. counter clock = 1MHz187.188. / 189. FreqBufcnt = (1000000L * 100) /190. tmp16; 191. /*100为扩大显示量程192. Freq_Value2=tmp16_CH3;193.194. 195. 196.197.198. if(TIM_GetITStatus(TIM4, TIM_IT_CC4) = SET)199.200. 201. 202. TIM_ClearITPendingBit(TIM4, TIM_IT_CC4);203. if(capture_number_CH4 = 0)204.205. 206.207. 208. capture_number_CH4 = 1;209.210. 211. last_time_CH4 = TIM_GetCapture4(TIM4);212.213. 214.215. else if(capture_number_CH4 = 1)216.217. 218.219. 220. capture_number_CH4 = 0;221.222. 223. this_time_CH4 = TIM_GetCapture4(TIM4);224. 225. if(this_time_CH4 last_time_CH4)226.227. 228.229. 230. tmp16_CH4 = (this_time_CH4 - last_time_CH4);231.232. 233.234. else235.236. 237.238. 239. tmp16_CH4 = (0xFFFF - last_time_CH4) + this_time_CH4);240.241. 242. /TIM2243. co