//main()函数前面的
	extern TIM_HandleTypeDef htim2;
	extern TIM_HandleTypeDef htim3;

//main()函数内部额外添加的
	HAL_TIM_Base_Start_IT(&htim2);
	HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_1);
	HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_2);
	HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_3);
	HAL_TIM_PWM_Start(&htim2,TIM_CHANNEL_4);

	HAL_TIM_Base_Start_IT(&htim3);
	HAL_TIM_PWM_Start(&htim3,TIM_CHANNEL_3);

这里奇怪的是，这里的PWM并没有因为有4路就陷入了混乱，

  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_1) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.Pulse = 1500;
  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_2) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.Pulse = 2000;
  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_3) != HAL_OK)
  {
    Error_Handler();
  }
  sConfigOC.Pulse = 2500;
  if (HAL_TIM_PWM_ConfigChannel(&htim2, &sConfigOC, TIM_CHANNEL_4) != HAL_OK)
  {
    Error_Handler();
  }

 这是因为在初始化的时候，pulse参数已经绑定了htim1或者htim2或者htim3或者htim4.所以就没有发生混乱。那么在改变PWM的时候是怎么做到更改的呢？

__HAL_TIM_SET_COMPARE(&htim2,TIM_CHANNEL_1,100);

/**
  * @brief  Set the TIM Capture Compare Register value on runtime without calling another time ConfigChannel function.
  * @param  __HANDLE__ TIM handle.
  * @param  __CHANNEL__ TIM Channels to be configured.
  *          This parameter can be one of the following values:
  *            @arg TIM_CHANNEL_1: TIM Channel 1 selected
  *            @arg TIM_CHANNEL_2: TIM Channel 2 selected
  *            @arg TIM_CHANNEL_3: TIM Channel 3 selected
  *            @arg TIM_CHANNEL_4: TIM Channel 4 selected
  * @param  __COMPARE__ specifies the Capture Compare register new value.
  * @retval None
  */
#define __HAL_TIM_SET_COMPARE(__HANDLE__, __CHANNEL__, __COMPARE__) \
  (((__CHANNEL__) == TIM_CHANNEL_1) ? ((__HANDLE__)->Instance->CCR1 = (__COMPARE__)) :\
   ((__CHANNEL__) == TIM_CHANNEL_2) ? ((__HANDLE__)->Instance->CCR2 = (__COMPARE__)) :\
   ((__CHANNEL__) == TIM_CHANNEL_3) ? ((__HANDLE__)->Instance->CCR3 = (__COMPARE__)) :\
   ((__HANDLE__)->Instance->CCR4 = (__COMPARE__)))

应该就是改变CCR寄存器的值就可以立刻改PWM的值吧；

而前面HAL_TIM_PWM_ConfigChannel(）这个函数并没有改变以前那些htim1/2/3/4的CCR1/2/3/4的值，所以虽然更改了pulse值，但是不会影响已经赋值的那些htim的pulse值