[MCU] 上海航芯ACM32G103开发板学习笔记03(定时器应用和PWM输出)

qzc0927 2023-12-29 09:45 楼主

## ==5：定时器的应用==

### 5.1：基本定时器

2 路基本定时器。基本定时器包含一个 16 位自动装载计数器，由各自的可编程预分频器驱动。它们可以作为通用定时器提供时间基准。
基本定时器特性如下：
16 位自动重装载累加计数器
16 位可编程(可实时修改)预分频器，用于对输入的时钟按系数为 1～65536 之间的任意数值分频在更新事件(计数器溢出)时产生中断/DMA 请求。

我们使用TIM6来实现。

![image-20231229093604722](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229093604722.png)

软件编程实现思路：

1：时钟配置

```c
static void Clock_Configuration(void)
{
 __RCC_TIM6_CLK_ENABLE(); 
} 
```

2：中断配置

```c
static void NVIC_Configuration(void)
{
  NVIC_ClearPendingIRQ(TIM6_IRQn); 
  NVIC_EnableIRQ(TIM6_IRQn); 
} 
```

3：定时器初始化

```c
void TIM6_Init(void)
{
  uint32_t timer_clock; 
    
    TIM_Base_InitTypeDef TIM_TimeBaseStructure; 
  
  timer_clock = RCC_GetPCLK1Freq(); 
  
  if (RCC_GetHCLKFreq() != timer_clock)// if hclk/pclk != 1, then timer clk = pclk * 2
  {
   timer_clock =timer_clock << 1; 
  }
  
    TIM_TimeBaseStructure.ClockDivision = TIM_CLOCKDIVISION_DIV1; 
    TIM_TimeBaseStructure.CounterMode = TIM_COUNTERMODE_UP; 
    TIM_TimeBaseStructure.RepetitionCounter = 0;
    TIM_TimeBaseStructure.Prescaler = (timer_clock/TIM_CLOCK_FREQ) - 1;
    TIM_TimeBaseStructure.Period = (TIM_CLOCK_FREQ/1000)*1000 - 1;// 1000ms 
    
    TIM_TimeBase_Init(TIM6, &TIM_TimeBaseStructure);

/* TIM IT enable */
  TIM_ITConfig(TIM6, TIM_IT_Update, ENABLE);

/* TIM6 enable counter */
  TIM_Cmd(TIM6, ENABLE);    
}
```

4：中断函数处理

```c
void TIM6_IRQHandler(void)
{
    if (TIM6->SR & TIMER_SR_UIF)
    {
        TIM6_Update_IRQ();   
  TIM6->SR &= (~BIT0);  
    }

}
```

5：计时任务处理

```c
void tim6_task(void)
{    
    if(Timer_Update_Flag) 
    {
        DEBUG_LOG("Timer Update Occurs\n"); 
        Timer_Update_Flag = 0; 
    }
}
```

6：串口调试

![image-20231229092228354](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229092228354.png)

可以从串口调试助手可以看到，每隔1S定时器触发。

### 5.2：通用定时器

参考数据手册说明：

![image-20231229093209568](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229093209568.png)

![image-20231229093234316](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229093234316.png)

我们这里使用TIM1来输出PWM。使用PC8引脚。

![image-20231229093749616](C:\Users\qzc09\AppData\Roaming\Typora\typora-user-images\image-20231229093749616.png)

![image-20231229093822497](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229093822497.png)

软件编程思路如下：

1：时钟配置

```c
static void Clock_Configuration(void)
{
  __RCC_TIM1_CLK_ENABLE();  
  __RCC_GPIOC_CLK_ENABLE(); 
}

```

2：GPIO引脚配置

```c
static void GPIO_Configuration(void)
{    
    GPIO_InitTypeDef gpio_init;
    gpio_init.Pin = GPIO_PIN_8;//TIM1_CH1
    gpio_init.Mode = GPIO_MODE_AF_PP;    
    gpio_init.Pull = GPIO_NOPULL;  
    gpio_init.Alternate = GPIO_FUNCTION_1;  
  gpio_init.Drive = GPIO_DRIVE_LEVEL3;
    GPIO_Init(GPIOC, &gpio_init);  // PC8 
}
```

3：定时器1初始化配置

```C
#define PWM_OUTPUT_CHANNEL1  TIM_CHANNEL_1 
#define TIM_CLOCK_FREQ    (8000000U)

static void TIM1_Init(void)
{
  uint32_t timer_clock;  
    
    
    TIM_Base_InitTypeDef TIM_TimeBaseStructure;  
    TIM_OC_InitTypeDef Tim_OC_Init_Para; 
    
  
  timer_clock = RCC_GetPCLK2Freq(); 
  if (RCC_GetHCLKFreq() != timer_clock)// if hclk/pclk != 1, then timer clk = pclk * 2
  {
   timer_clock =timer_clock << 1;  
  }
  
    TIM_TimeBaseStructure.ClockDivision = TIM_CLOCKDIVISION_DIV1; 
    TIM_TimeBaseStructure.CounterMode = TIM_COUNTERMODE_UP; 
    TIM_TimeBaseStructure.RepetitionCounter = 0;
    TIM_TimeBaseStructure.Prescaler = (timer_clock/TIM_CLOCK_FREQ) - 1;
  if (timer_clock%TIM_CLOCK_FREQ > TIM_CLOCK_FREQ/2) 
    {
        TIM_TimeBaseStructure.Prescaler = TIM_TimeBaseStructure.Prescaler + 1;
    }
    TIM_TimeBaseStructure.Period = (TIM_CLOCK_FREQ/1000000)*10 - 1;// period = 10us, frequency = 100KHz       
    TIM_TimeBase_Init(TIM1, &TIM_TimeBaseStructure);  
  
    Tim_OC_Init_Para.OCMode = OUTPUT_MODE_PWM1;
    Tim_OC_Init_Para.OCIdleState = OUTPUT_IDLE_STATE_0;
    Tim_OC_Init_Para.OCNIdleState = OUTPUT_IDLE_STATE_0;  
    Tim_OC_Init_Para.OCPolarity = OUTPUT_POL_ACTIVE_HIGH;
    Tim_OC_Init_Para.OCNPolarity = OUTPUT_POL_ACTIVE_HIGH;  
    Tim_OC_Init_Para.OCFastMode =OUTPUT_FAST_MODE_DISABLE;
    Tim_OC_Init_Para.Pulse = (TIM_TimeBaseStructure.Period + 1)/2; // 50% duty cycle     
    TIM_OC1Init(TIM1, &Tim_OC_Init_Para);     
     
}

```

4：PWM输出配置

```C
voidbsp_tim1_init(void)
{
  Clock_Configuration();  
  
  GPIO_Configuration(); 
  
    TIM1_Init(); 
  
  TIM_CCxCmd(TIM1, TIM_CHANNEL_1, TIM_CCx_Enable);   
  /* TIM1 enable counter */  
  TIM_Cmd(TIM1, ENABLE); 
  
  /* Main Output Enable */
  TIM_CtrlPWMOutputs(TIM1, ENABLE); 
}
```

5：示波器上查看波形

将PC8引脚接到探针里面，查看PWM输出波形。

![image-20231229094150895](https://boreyun.oss-cn-shanghai.aliyuncs.com/image-20231229094150895.png)