想来定时器PWM实现呼吸灯也是挺有意思的一件事情。其实呼吸灯的原理还是挺简单的,就是不断的调整信号的占空比,来实现信号灯的逐渐变亮变暗的效果。 查看Datasheet,正好板卡上的LED脚PA5对应TIM2_CH1,这样实现起来就方便多了。 这次必须说一下时钟,程序使用的传统的HSI 16M时钟。预分频器16,这样实现100HZ的频率就能计算周期和占空比了。剩下的就都是套路了。 引脚初始化: - GPIO_InitStruct.Pin = GPIO_PIN_5;+ I% C' m3 Z4 s; u n7 K; A
- GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;+ R4 r3 O% d M n- [5 i
- GPIO_InitStruct.Pull = GPIO_PULLUP;1 c1 W( k0 K& F0 e" P
- GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;1 {6 `8 |5 c" e' G3 N- G
- GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;5 Z) J! z' u2 q+ H ?* ?4 N
8 l. i6 W+ K: W/ z3 l% |- // GPIO_InitStruct.Pin = GPIO_PIN_5;
9 ~0 y0 j4 j( l) b% ^. j - HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
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定时器初始化如下: - __HAL_RCC_TIM2_CLK_ENABLE();
$ r3 D+ V' ~5 Y3 t& \! v/ n - // TIM_HandleTypeDef htim1;! a) ?6 p) n4 q7 I7 M4 q
- TIM_MasterConfigTypeDef sMasterConfig;
/ |3 u# p9 H- J% | - TIM_OC_InitTypeDef sConfigOC;
$ t! m4 L- j. g' t7 x. { - TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig;
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- /* USER CODE BEGIN TIM1_Init 1 */
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, i. U( p( n* b) [- /* USER CODE END TIM1_Init 1 */# h% y* E; x7 r; c7 f4 f
- htim1.Instance = TIM2;
: {" q% {0 n$ P5 X - htim1.Init.Prescaler = 16;//PRESCALER_VALUE;9 q( s+ G1 U& s( t# i# G0 y) x8 O
- htim1.Init.CounterMode = TIM_COUNTERMODE_UP;( c/ F/ S* t% c5 d$ ^6 i; D6 Z. ^9 h
- htim1.Init.Period = 10000-1;//PERIOD_VALUE;1 E- A6 B) x* m4 i& r
- htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
! ]9 w9 X& g# D) l. E: M! X" @ - htim1.Init.RepetitionCounter = 0;
- f/ X5 Y$ M* S! S: l5 T( b6 {, L/ | - htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
% J& E) e+ H/ q$ i% g5 I - if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)2 `* ]( x7 ^2 `- M5 Q
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- Error_Handler();
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- sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
8 D. q5 E1 m6 k; c9 B - sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
: I9 H8 S g3 f; a3 N# e5 } - sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;# z- o$ T8 g; O; p, G5 e5 @' w0 {
- if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)/ Y) Z, e( _& A, \6 z/ W$ O
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- Error_Handler();+ m& W6 d" q1 {. Z* V8 e" R# Y, z
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- sConfigOC.OCMode = TIM_OCMODE_PWM1;4 g3 _7 d8 V; O E, e: j, Z. v. s
- sConfigOC.Pulse = 5000-1;//PULSE1_VALUE;! t, z1 f3 L+ ?- g- |
- sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;0 \, D7 q1 g: y
- sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;$ K$ d- s3 I4 M9 I* h( o
- sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;+ r, \' I! ~# V* z; Z* W* d
- sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
% F; f0 @3 Q; H6 x, o' z - sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;; O, P3 l+ A+ X0 v' Q: V! Q8 B% o
- if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)& v3 W, w; V+ X: T4 r
- {
1 B2 V$ f6 z4 b3 r+ ]/ e - Error_Handler();
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- HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
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在while循环中不断的修改占空比,部分修改如下: - Value+=200;
4 V. F& q! d2 I9 ^! p; T- O - HAL_Delay(20);- G* p5 k5 { y7 m2 N
- PWM_Chang(Value);4 |) v* H# r3 s8 T% s- s
- if(Value>=9000)2 ~0 D, Q9 e" @
- flag =1;
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}+ X/ r$ T) B6 D, J( K最终效果如图所示:
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不如把示波器的波形图也贴上来
是的