HAL library encoding speed DC motor (drive L298N) Notes

The main function after the start of the processing flow:

1. peripheral initialization: HAL_Init ()

2. The system clock configuration

• RCC oscillator Initialization: HAL_RCC_OsConfig ()
• RCC clock initialization: HAL_RCC_ClockConfig ()
• The system tick timer initialization: HAL_SYSTICK_Config ()

3. Key GPIO initialization

• GPIO Port Clock Enable: __ HAL_RCC_GPIOA_CLK_ENABLE ()
• Operating mode
• Activating the pull-down or pull-
• Pin Initialization: HAL_GPIO_Init ()

 

4. serial port initialization

• Serial GPIO port is enabled: __ HAL_RCC_GPIOA_CLK_ENABLE ()
• Serial port initialization (containing the serial port hardware initialization): HAL_UART_Init ()

 

The timer is initialized encoder

• Timer Clock Enable: __ HAL_RCC_TIM3_CLK_ENABLE ()
• GPIO pins are initialized encoder
  • GPIO Port Clock Enable: __ HAL_RCC_GPIOB_CLK_ENABLE ()
  • Operating mode
  • Activating the pull-down or pull-
  • Pin Initialization: HAL_GPIO_Init ()
• Interrupt priority encoder configuration
  • Set the interrupt priority: HAL_NVIC_SetPriority ()
  • Enable interrupt request: HAL_NVIC_EnableIRQ ()
• Basic environmental timer initialization: HAL_TIM_Base_Init ()
• Timer Clock Source: HAL_TIM_ConfigClockSource ()
• Timer input capture environment initialization: HAL_TIM_IC_Init ()
• Output synchronization master timer mode: HAL_TIMEx_MasterConfigSynchronization ()
• Timer input capture configuration: HAL_TIM_IC_ConfigChannel ()

 

6. The encoder timer is started: HAL_TIM_Base_Start ()

 

7.L298N timer initialization

• Basic environment initialization: HAL_TIM_Base_Init ()
• Clock Source: HAL_TIM_ConfigClockSource ()
• Initialization comparison output (mcu comprises hardware initialization): HAL_TIM_PWM_Init ()
  • Initialization: HAL_TIM_Base_MspInit ()
  • Deinitialization: HAL_TIM_Base_MspDeInit ()
• Output synchronization master mode: HAL_TIMEx_MasterConfigSynchronization ()
• Brakes and dead-time configuration: HAL_TIMEx_ConfigBreakDeadTime ()
• Comparator Output Configuration: HAL_TIM_PWM_ConfigChannel ()
  • Timer actual clock frequency: 72MHz / (timer prescaler +1) = 36MHz
  • PWM frequency is: timer actual clock frequency / (timer period +1), [900, then the timer period, 36MHz / (900 + 1) = 40Khz]
  • The actual frequency PWM: PWM frequency / (Advanced timer Repeat Count Register value of +1), [Advanced timer repeatedly count register value is 0, then, 40KHz / 0 + 1 = 40KHz]
  • The PWM duty cycle is: Comparator output pulse timer / timer cycle * 100%, 50% duty cycle the motor does not rotate. [Comparative channel output pulse timer 450, the timer period is 900, then the 50% duty cycle, the motor does not turn]
• GPIO pins are initialized
  • a.GPIO Port Clock Enable: __ HAL_RCC_GPIOA_CLK_ENABLE ()
  • b Set IO pins:. Pin
  • c Set operating mode:. Mode
  • d Set Speed:. Speed
  • . E complete initialization: HAL_GPIO_Init ()

 

8. encoder capture timer interrupt start: HAL_TIM_IC_Start_IT ()

 

9. The L298N PWM channel timer channels and a complementary output (motor can be controlled forward and reverse)

• HAL_TIM_PWM_Start() 、
• HAL_TIMEx_PWMN_Start()

 

10 cycles: the while (. 1) {}

 

Remarks:

The system tick timer interrupt callback function (tick timer interrupt occurs once every access to the callback function once): HAL_SYSTICK_Callback ()

Input capture timer interrupt callback function: HAL_TIM_IC_CaptureCallback ()

Redirection C library function printf: int fputc (int ch, FILE * f) {}

Redirection C library function getchar, scanf: int fgetc (FILE * f) {}