PWM
通过控制方波中低平信号长度来控制LED亮度或电机速度。
初始化
Timers内选择一个定时器（以TIM1为例）。Clock Source选择Internal Clock, 选择一个Channel（例如Channel 1）选择PWM Generation CH1, 这时PA8就被选定，我们可以用LED0测试PWM效果了
Prescaler: 72-1
Period: 1000-1
Pulse: 500
这样frequency大致为1000hz（PWMf=TIMf/(prescaler+1)*(Period+1)）
PWM.c
需自行加入TIM_SetTIM1Compare函数，更改CCR值。
在Init函数结尾加上 HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1); 开启pwm
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| //TIM1 channel 1, works on PA8
//default psc=72-1, arr=1000-1, pulse=500(almost 50%)
//in this case the frequency is 1000hz
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
TIM_HandleTypeDef htim1;
/* TIM1 init function */
void MX_TIM1_Init(void)
{
/* USER CODE BEGIN TIM1_Init 0 */
/* USER CODE END TIM1_Init 0 */
TIM_MasterConfigTypeDef sMasterConfig = {0};
TIM_OC_InitTypeDef sConfigOC = {0};
TIM_BreakDeadTimeConfigTypeDef sBreakDeadTimeConfig = {0};
/* USER CODE BEGIN TIM1_Init 1 */
/* USER CODE END TIM1_Init 1 */
htim1.Instance = TIM1;
htim1.Init.Prescaler = 72-1;
htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
htim1.Init.Period = 1000-1;
htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
htim1.Init.RepetitionCounter = 0;
htim1.Init.AutoReloadPreload = TIM_AUTORELOAD_PRELOAD_DISABLE;
if (HAL_TIM_PWM_Init(&htim1) != HAL_OK)
{
Error_Handler();
}
sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig) != HAL_OK)
{
Error_Handler();
}
sConfigOC.OCMode = TIM_OCMODE_PWM1;
sConfigOC.Pulse = 500;
sConfigOC.OCPolarity = TIM_OCPOLARITY_HIGH;
sConfigOC.OCNPolarity = TIM_OCNPOLARITY_HIGH;
sConfigOC.OCFastMode = TIM_OCFAST_DISABLE;
sConfigOC.OCIdleState = TIM_OCIDLESTATE_RESET;
sConfigOC.OCNIdleState = TIM_OCNIDLESTATE_RESET;
if (HAL_TIM_PWM_ConfigChannel(&htim1, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
{
Error_Handler();
}
sBreakDeadTimeConfig.OffStateRunMode = TIM_OSSR_DISABLE;
sBreakDeadTimeConfig.OffStateIDLEMode = TIM_OSSI_DISABLE;
sBreakDeadTimeConfig.LockLevel = TIM_LOCKLEVEL_OFF;
sBreakDeadTimeConfig.DeadTime = 0;
sBreakDeadTimeConfig.BreakState = TIM_BREAK_DISABLE;
sBreakDeadTimeConfig.BreakPolarity = TIM_BREAKPOLARITY_HIGH;
sBreakDeadTimeConfig.AutomaticOutput = TIM_AUTOMATICOUTPUT_DISABLE;
if (HAL_TIMEx_ConfigBreakDeadTime(&htim1, &sBreakDeadTimeConfig) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN TIM1_Init 2 */
/* USER CODE END TIM1_Init 2 */
HAL_TIM_MspPostInit(&htim1);
HAL_TIM_PWM_Start(&htim1, TIM_CHANNEL_1);
}
void HAL_TIM_PWM_MspInit(TIM_HandleTypeDef* tim_pwmHandle)
{
if(tim_pwmHandle->Instance==TIM1)
{
/* USER CODE BEGIN TIM1_MspInit 0 */
/* USER CODE END TIM1_MspInit 0 */
/* TIM1 clock enable */
__HAL_RCC_TIM1_CLK_ENABLE();
/* USER CODE BEGIN TIM1_MspInit 1 */
/* USER CODE END TIM1_MspInit 1 */
}
}
void HAL_TIM_MspPostInit(TIM_HandleTypeDef* timHandle)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(timHandle->Instance==TIM1)
{
/* USER CODE BEGIN TIM1_MspPostInit 0 */
/* USER CODE END TIM1_MspPostInit 0 */
__HAL_RCC_GPIOA_CLK_ENABLE();
/**TIM1 GPIO Configuration
PA8 ------> TIM1_CH1
*/
GPIO_InitStruct.Pin = GPIO_PIN_8;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/* USER CODE BEGIN TIM1_MspPostInit 1 */
/* USER CODE END TIM1_MspPostInit 1 */
}
}
void HAL_TIM_PWM_MspDeInit(TIM_HandleTypeDef* tim_pwmHandle)
{
if(tim_pwmHandle->Instance==TIM1)
{
/* USER CODE BEGIN TIM1_MspDeInit 0 */
/* USER CODE END TIM1_MspDeInit 0 */
/* Peripheral clock disable */
__HAL_RCC_TIM1_CLK_DISABLE();
/* USER CODE BEGIN TIM1_MspDeInit 1 */
/* USER CODE END TIM1_MspDeInit 1 */
}
}
void TIM_SetTIM1Compare(long int compare)
{
TIM1->CCR1=compare;
}
void Compare_Value_Setting(void)
{
static uint8_t pwm_compare_state=0;
static long int PWM_COMPARE=0;
if (PWM_COMPARE==0) pwm_compare_state=1;
if (PWM_COMPARE>htim1.Init.Period) pwm_compare_state=0;
if (pwm_compare_state){
PWM_COMPARE+=10;
TIM_SetTIM1Compare(PWM_COMPARE);
}
else {
PWM_COMPARE-=10;
TIM_SetTIM1Compare(PWM_COMPARE);
}
}
|
PWM.h
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|
extern "C" {
/* Includes ------------------------------------------------------------------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
extern TIM_HandleTypeDef htim1;
/* USER CODE BEGIN Private defines */
/* USER CODE END Private defines */
void MX_TIM1_Init(void);
void HAL_TIM_MspPostInit(TIM_HandleTypeDef *htim);
/* USER CODE BEGIN Prototypes */
void TIM_SetTIM1Compare(long int compare);
void Compare_Value_Setting(void);
/* USER CODE END Prototypes */
}
|
实例
LED0会缓慢变亮又变暗,LED初始化必须在TIM1之前。
注意： 如果灯长暗或长亮，检查是不是最开channel里没选pwm generation这类。
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void SystemClock_Config(void);
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_TIM1_Init();
while (1)
{
Compare_Value_Setting();
HAL_Delay(10);
}
}
|