STM32F103_TIM3输出PWM波实现全彩呼吸灯
一、LED灯
1. 必须是全彩RGB_LED灯
2. 通过不同的红绿蓝三色LED混合出256种颜色，同电脑画图里的调色RGB888，每个灯各用8位控制其亮度，其中全灭表示黑色。
二、
1. LED亮度等级表
/* LED亮度等级 PWM表,指数曲线 ，此表使用工程目录下的python脚本index_wave.py生成*/
const uint16_t indexWave[] = {
1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2,
2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5,
5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10,
11, 12, 12, 13, 14, 15, 17, 18,
19, 20, 22, 23, 25, 27, 29, 31,
33, 36, 38, 41, 44, 47, 51, 54,
58, 63, 67, 72, 77, 83, 89, 95,
102, 110, 117, 126, 135, 145, 156,
167, 179, 192, 206, 221, 237, 254,
272, 292, 313, 336, 361, 387, 415,
445, 477, 512, 512, 477, 445, 415,
387, 361, 336, 313, 292, 272, 254,
237, 221, 206, 192, 179, 167, 156,
145, 135, 126, 117, 110, 102, 95,
89, 83, 77, 72, 67, 63, 58, 54, 51,
47, 44, 41, 38, 36, 33, 31, 29, 27,
25, 23, 22, 20, 19, 18, 17, 15, 14,
13, 12, 12, 11, 10, 9, 9, 8, 8, 7, 7,
6, 6, 5, 5, 5, 4, 4, 4, 4, 3, 3, 3,
3, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1
};2. 各项参数宏定义
extern uint16_t POIT_NUM;
extern __IO uint16_t period_class;
/*电压幅值等级数*/
#define AMPLITUDE_CLASS 256
/*****************定时器通道**************************/
#define BREATH_TIMx TIM3
#define BREATH_TIM_APBxClock_FUN RCC_APB1PeriphClockCmd
#define BREATH_TIM_CLK RCC_APB1Periph_TIM3
/*****************红灯**************************/
#define BREATH_RED_LED_PORT GPIOB
#define BREATH_RED_LED_PIN GPIO_Pin_5
#define BREATH_RED_CCRx CCR2
#define RED_TIM_OCxInit TIM_OC2Init
#define RED_TIM_OCxPreloadConfig TIM_OC2PreloadConfig
/*****************绿灯**************************/
#define BREATH_GRE_LED_PORT GPIOB
#define BREATH_GRE_LED_PIN GPIO_Pin_0
#define BREATH_GRE_CCRx CCR3
#define GRE_TIM_OCxInit TIM_OC3Init
#define GRE_TIM_OCxPreloadConfig TIM_OC3PreloadConfig
/*****************蓝灯**************************/
#define BREATH_BLU_LED_PORT GPIOB
#define BREATH_BLU_LED_PIN GPIO_Pin_1
#define BREATH_BLU_CCRx CCR4
#define BLU_TIM_OCxInit TIM_OC4Init
#define BLU_TIM_OCxPreloadConfig TIM_OC4PreloadConfig
#define BREATH_LED_REMAP_FUN() GPIO_PinRemapConfig(GPIO_PartialRemap_TIM3 ,ENABLE);
//中断
#define BREATH_TIM_IRQHandler TIM3_IRQHandler
三、breathing_led.c 编写
1. GPIO配置函数，其中red灯用TIM3_CH2,其由PB5部分重映射而来，因此在配置时必须开启AFIO时钟，并重映射。
__IO uint16_t period_class = 1;//pwm表中的每个数据只使用一次
uint16_t POIT_NUM = sizeof(indexWave) / sizeof (indexWave[0]); //计算pwm表中一共有多少数据，数据表应放在此条语句之前
static void Breath_LED_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_AFIO, ENABLE); //重映射时必须开启AFIO时钟
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
BREATH_LED_REMAP_FUN();
GPIO_InitStructure.GPIO_Pin = BREATH_RED_LED_PIN;
GPIO_Init(BREATH_RED_LED_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = BREATH_GRE_LED_PIN;
GPIO_Init(BREATH_GRE_LED_PORT, &GPIO_InitStructure);
GPIO_InitStructure.GPIO_Pin = BREATH_BLU_LED_PIN;
GPIO_Init(BREATH_BLU_LED_PORT, &GPIO_InitStructure);
}
2. 中断向量表配置，只用到定时器3中断，因而中断优先级可任意配置。
/**
* @brief 中断参数配置
* @param 无
* @retval 无
*/
static void Breath_NVIC_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);
NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
NVIC_Init(&NVIC_InitStructure);
}3. 定时器模式配置函数，其中低电平led量，因而PWM有效电平为low，占空比通过TIM_TimeBaseInitStructure.TIM_Period ，TIM_OCInitStructure.TIM_Pulse 来配置，初始化占空比为0；
static void Breath_TIM_Config(void)
{
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_OCInitTypeDef TIM_OCInitStructure;
//开时钟
BREATH_TIM_APBxClock_FUN(BREATH_TIM_CLK, ENABLE);
TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInitStructure.TIM_Period = (512 - 1);
TIM_TimeBaseInitStructure.TIM_Prescaler =(10 - 1);
TIM_TimeBaseInit(BREATH_TIMx, &TIM_TimeBaseInitStructure);
//输出比较配置
TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_Low; /********************配置为低的原因是 低电平点亮LED灯**********************/
TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable ;
TIM_OCInitStructure.TIM_Pulse = 0;
RED_TIM_OCxInit(BREATH_TIMx, &TIM_OCInitStructure);
RED_TIM_OCxPreloadConfig (BREATH_TIMx, TIM_OCPreload_Enable ); //预装载使能
GRE_TIM_OCxInit(BREATH_TIMx, &TIM_OCInitStructure);
GRE_TIM_OCxPreloadConfig (BREATH_TIMx, TIM_OCPreload_Enable );
BLU_TIM_OCxInit(BREATH_TIMx, &TIM_OCInitStructure);
BLU_TIM_OCxPreloadConfig (BREATH_TIMx, TIM_OCPreload_Enable );
TIM_ARRPreloadConfig (BREATH_TIMx, ENABLE);//一定要使能自动重装载
TIM_Cmd (BREATH_TIMx, ENABLE);
//中断开启
TIM_ITConfig(BREATH_TIMx, TIM_IT_Update, ENABLE);
//中断优先级
Breath_NVIC_Config();
}.4. 初始化
void Breath_LED_Init(void)
{
Breath_LED_Config();
Breath_TIM_Config();
}四、中断函数，关键点为将每个亮度等级（一共有512个亮度等级，也就是TIM_Period的值）又分为256个等级，通过对比设定参数与实际参数控制LED亮灭来实现调色。
extern uint16_t indexWave[];
extern __IO uint32_t rgb_color;
void BREATH_TIM_IRQHandler(void)
{
static uint16_t period_cnt = 0;
static uint16_t pwm_index = 0;
static uint16_t amplitude_cnt = 0;//计算幅值等级
if(TIM_GetFlagStatus (BREATH_TIMx, TIM_FLAG_Update) == SET)
{
amplitude_cnt ++;
if(amplitude_cnt > AMPLITUDE_CLASS)
{
period_cnt ++;
if(period_cnt > period_class)
{
period_cnt = 0;
pwm_index ++;
if(pwm_index >= POIT_NUM)
{
pwm_index = 0;
}
}
amplitude_cnt = 0;
}
else
{
if(((rgb_color & 0xff0000) >> 16) >= amplitude_cnt)
BREATH_TIMx -> BREATH_RED_CCRx = indexWave[pwm_index];
else
BREATH_TIMx -> BREATH_RED_CCRx = 0;
if(((rgb_color & 0x00ff00) >> 8) >= amplitude_cnt)
BREATH_TIMx -> BREATH_GRE_CCRx = indexWave[pwm_index];
else
BREATH_TIMx -> BREATH_GRE_CCRx = 0;
if((rgb_color & 0xff) >=amplitude_cnt)
BREATH_TIMx -> BREATH_BLU_CCRx = indexWave[pwm_index];
else
BREATH_TIMx -> BREATH_BLU_CCRx = 0;
}
TIM_ClearITPendingBit (BREATH_TIMx, TIM_IT_Update);
}五、主函数
#include "breathing_led.h"
#define SOFT_DELAY() Delay(0xFFFFFF); //通过设定此参数来实现指定颜色，其值可通过电脑-画图-编辑颜色算得
__IO uint32_t rgb_color = 0x9CE326; // 156 227 38，此参数用来设置混合的颜色
int main()
{
Breath_LED_Init();
while(1)
;
}为了便于获得工程文件，在此贴上下载链接：
链接：https://pan.baidu.com/s/1fjI1dBRzc4a3m7592nfAjA
提取码：1ufm