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;4 l8 R) p( P' P4 c4 w: ]
- GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
# n# D9 T r, }9 @& j/ A- n% e - GPIO_InitStruct.Pull = GPIO_PULLUP;
% q$ G* L; f7 | b2 x3 K/ | - GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
+ m" Z" l! l& u4 B - GPIO_InitStruct.Alternate = GPIO_AF1_TIM2;
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( C/ j. }0 U4 `) u( Q# B- // GPIO_InitStruct.Pin = GPIO_PIN_5;0 k. o- _7 h: I% D5 c
- HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
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定时器初始化如下: - __HAL_RCC_TIM2_CLK_ENABLE();
# L# [: E8 c; X) v* m# u - // TIM_HandleTypeDef htim1;$ s' N1 v' b# R
- TIM_MasterConfigTypeDef sMasterConfig;4 [' d) ]8 {/ o- {* g1 k
- TIM_OC_InitTypeDef sConfigOC;5 }+ i( p0 s) p. U1 _
- TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig;
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- /* USER CODE BEGIN TIM1_Init 1 */' v1 r3 ]( T6 t- b
% s1 D7 r- g' Q2 x4 p- /* USER CODE END TIM1_Init 1 */2 C( v! Z: W$ M, N3 ?
- htim1.Instance = TIM2;# ], C y+ q* \6 P) i4 f
- htim1.Init.Prescaler = 16;//PRESCALER_VALUE;
/ B: S0 I: z/ K# t - htim1.Init.CounterMode = TIM_COUNTERMODE_UP;& M1 ^8 J- H: {' G) A5 v
- htim1.Init.Period = 10000-1;//PERIOD_VALUE;9 c# Z$ d6 `- ?& ?( B% @5 S+ j
- htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
. U) @4 ~, {6 T! H1 s" g - htim1.Init.RepetitionCounter = 0;; |+ N: P# t% d( {
- htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
- |& m* P) H- k* J5 F t/ G) i - if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)0 m! V! t. @6 ` u; H2 w6 K0 X: g" Z
- {
1 @9 t$ u/ P d2 H - Error_Handler();6 W) {8 h* p# ~$ Q: M0 _; ]( p
- }
! f3 [3 R9 i! Q. k. S: o$ N. t6 C: b - sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
+ r8 E+ p7 T9 Z" L9 N - sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
9 Q8 N" n& K/ A9 h+ a* m" Q+ V - sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
$ L8 y* y$ X6 f& p6 B - if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)& G' }/ Q5 o/ e4 j6 X
- {
7 ^4 n5 x$ F0 l0 O! m, x& M - Error_Handler();
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; G, l+ Q0 E2 K3 U! y5 o9 N - sConfigOC.OCMode = TIM_OCMODE_PWM1;2 @- I" ~2 j5 E7 f5 F4 _- R. P5 T
- sConfigOC.Pulse = 5000-1;//PULSE1_VALUE;
$ v/ i" W2 r6 U! p - sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;5 s }* h/ a p9 z5 V- J
- sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;- ?. }" s+ M1 |! n1 c- T( g
- sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;; I* M5 B& ~: l7 @
- sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;, D, b* } @/ ~9 i; P" p
- sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
8 I2 a+ I9 R% s. _ - if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
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- Error_Handler();9 c& S0 W. `8 _2 K0 p
- }
4 L, K* V/ f: i1 t( y' S4 q - HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
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' A: ?; [# g q( ]0 l. D在while循环中不断的修改占空比,部分修改如下: - Value+=200;' u2 w# ]) d5 ~. o: T! ]* b, `
- HAL_Delay(20);. y# @. h" ], d+ f
- PWM_Chang(Value);
2 `8 d0 o' `( [% [2 Q) B - if(Value>=9000)- s' p; J9 E5 s% I, O
- flag =1;
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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