1. The timer serial port lights up the LED light regularly
Create a project using HAL library
Open STM32CubeMX and click on the main interface: ACCESS TO MCU SELECTOR:
Select the microcontroller model and click to start the project (this article uses STM32103C8T6)
Configure RCC
Configure SYS
Configure IO port output
Here, PA0 is selected as the output of the LED light, and it is selected as GPIO-OUT. Here we only use one light for demonstration purposes.
Configure TIM2 TIM3
Configure NVIC
Configure USART
Enter CLK Configuration (clock configuration) to configure the clock
Enter Project Manager (project management), perform project settings, click Generate project and code, and generate code after completion
Improving the keil5 project
Modify the main.c file as follows
/* USER CODE BEGIN Header */
/**
*************************************************** ******************************
* @file: main.c
* @brief: Main program body
*************************************************** ******************************
*@attention
*
* Copyright (c) 2022 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
*************************************************** ******************************
*/
/* USER CODE END Header */
/* Includes ----------------------------------------------- ------------------*/
#include "main.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
/* Private includes -------------------------------------------------- ----------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
/* Private typedef ----------------------------------------------- -------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define -------------------------------------------------- ---------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro ----------------------------------------------- ---------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables -------------------------------------------------- -----------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes ------------------------------------------------ --*/
void SystemClock_Config(void);
static void MX_NVIC_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/*Private user code--------------------------------------------- ----------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
uint8_t hello[20]="hello windows!\r\\
";
int main(void)
{<!-- -->
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration------------------------------------------------- ----------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_TIM2_Init();
MX_TIM3_Init();
MX_USART1_UART_Init();
/* Initialize interrupts */
MX_NVIC_Init();
HAL_TIM_Base_Start_IT( & amp;htim2);
HAL_TIM_Base_Start_IT( & amp;htim3);
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{<!-- -->
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{<!-- -->
RCC_OscInitTypeDef RCC_OscInitStruct = {<!-- -->0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {<!-- -->0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig( & amp;RCC_OscInitStruct) != HAL_OK)
{<!-- -->
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig( & amp;RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{<!-- -->
Error_Handler();
}
}
/**
* @brief NVIC Configuration.
* @retval None
*/
static void MX_NVIC_Init(void)
{<!-- -->
/* TIM2_IRQn interrupt configuration */
HAL_NVIC_SetPriority(TIM2_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(TIM2_IRQn);
/* TIM3_IRQn interrupt configuration */
HAL_NVIC_SetPriority(TIM3_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(TIM3_IRQn);
}
/* USER CODE BEGIN 4 */
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{<!-- -->
static uint32_t time_cnt =0;
static uint32_t time_cnt3 =0;
if(htim->Instance == TIM2)
{<!-- -->
if( + + time_cnt >= 400)
{<!-- -->
time_cnt =0;
HAL_GPIO_TogglePin(GPIOA,GPIO_PIN_0);
}
}
if(htim->Instance == TIM3)
{<!-- -->
if( + + time_cnt3 >= 1000)
{<!-- -->
time_cnt3 =0;
HAL_UART_Transmit( & amp;huart1,hello,20,100000);
}
\t\t\t
}
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{<!-- -->
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{<!-- -->
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{<!-- -->
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\\
", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
Run results
2. PWM completed breathing light
Create a project using HAL library
Open STM32CubeMX and click on the main interface: ACCESS TO MCU SELECTOR:
Select the microcontroller model and click to start the project (this article uses STM32103C8T6)
Enter CLK Configuration (clock configuration) to configure the clock
Configure TIM4
Configure TIM3
Configure SYS
Configure RCC
Enter Project Manager (project management), perform project settings, click Generate project and code, and generate code after completion
Improving the keil5 project
Modify the main.c file as follows
/* USER CODE BEGIN Header */
/**
*************************************************** ******************************
* @file: main.c
* @brief: Main program body
*************************************************** ******************************
*@attention
*
* Copyright (c) 2023 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
*************************************************** ******************************
*/
/* USER CODE END Header */
/* Includes ----------------------------------------------- ------------------*/
#include "main.h"
#include "tim.h"
#include "gpio.h"
/* Private includes -------------------------------------------------- ----------*/
/* USER CODE BEGIN Includes */
/* USER CODE END Includes */
/* Private typedef ----------------------------------------------- -------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define -------------------------------------------------- ---------------*/
/* USER CODE BEGIN PD */
/* USER CODE END PD */
/* Private macro ----------------------------------------------- ---------------*/
/* USER CODE BEGIN PM */
/* USER CODE END PM */
/* Private variables -------------------------------------------------- -----------*/
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes ------------------------------------------------ --*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/*Private user code--------------------------------------------- ----------*/
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
uint16_t duty_num3 = 10;
uint16_t duty_num4 = 10;
int main(void)
{<!-- -->
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration------------------------------------------------- ----------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_TIM3_Init();
MX_TIM4_Init();
HAL_TIM_PWM_Start( & amp;htim3,TIM_CHANNEL_1);
HAL_TIM_PWM_Start( & amp;htim4,TIM_CHANNEL_1);
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{<!-- -->
/* USER CODE END WHILE */
HAL_Delay(50);
duty_num3 = duty_num3 + 10;
duty_num4 = duty_num4 + 10;
if(duty_num3 > 500)
{<!-- -->
duty_num3 = 0;
}
__HAL_TIM_SetCompare( & amp;htim3,TIM_CHANNEL_1,duty_num3);
if(duty_num4 > 500)
{<!-- -->
duty_num4 = 0;
}
__HAL_TIM_SetCompare( & amp;htim4,TIM_CHANNEL_1,duty_num4);
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{<!-- -->
RCC_OscInitTypeDef RCC_OscInitStruct = {<!-- -->0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {<!-- -->0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig( & amp;RCC_OscInitStruct) != HAL_OK)
{<!-- -->
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig( & amp;RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{<!-- -->
Error_Handler();
}
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{<!-- -->
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{<!-- -->
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{<!-- -->
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\\
", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
Run results
Keil virtual oscilloscope, observe pwm output waveform
Click on the first step. In the Target interface, select the correct crystal oscillator size and use an 8MHz external crystal oscillator.
Then proceed to the settings of the Debug page
Choose a logic analyzer
Click Setup to add the pins to be observed.
We directly choose to add and write PORTA.6
The following are the simulation results
3. The timer pwm completes the breathing light and the collection and capture of the pwm output signal
Create a project using HAL library
Open STM32CubeMX and click on the main interface: ACCESS TO MCU SELECTOR:
Select the microcontroller model and click to start the project (this article uses STM32103C8T6)
Configure TIM1
Configure TIM2
Configure USART1
Configure SYS
Configure RCC
As shown in the figure below, select the corresponding microcontroller port configuration and use 
Enter Project Manager (project management), perform project settings, click Generate project and code, and generate code after completion
Improving the keil5 project
Modify the main.c file as follows
#include "main.h"
#include "tim.h"
#include "usart.h"
#include "gpio.h"
uint8_t i = 0;
floatDuty = 0;
float Frequency = 0;
uint16_t Cap_val1 = 0;
uint16_t Cap_val2 = 0;
int main(void)
{<!-- -->
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_TIM1_Init();
MX_TIM3_Init();
MX_USART1_UART_Init();
MX_TIM2_Init();
/* USER CODE BEGIN WHILE */
printf("Serial communication test\r\\
");
HAL_TIM_Base_Start_IT( & amp;htim2); // Enable timer and its update interrupt
HAL_TIM_PWM_Start( & amp;htim3, TIM_CHANNEL_1); // Enable the timer and its PWM output
HAL_TIM_IC_Start_IT( & amp;htim1, TIM_CHANNEL_1); // Enable timer and its input capture
HAL_TIM_IC_Start_IT( & amp;htim1, TIM_CHANNEL_2); // Enable timer and its input capture
__HAL_TIM_SET_COMPARE( & amp;htim3, TIM_CHANNEL_1, 10); // Set a PWM waveform for measurement
while (1)
{<!-- -->
// Serial port transmission frequency duty cycle
printf("Cap_val1 is :%d , Cap_val2 is : %d \r\\
", Cap_val1, Cap_val2);
printf("Duty is :%0.2f%% Frequency is : %0.2f ms\r\\
", Duty, Frequency);
HAL_Delay(1000);
}
}
//Interrupt function for scheduled TIM2 scheduled lighting
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *tim)
{<!-- -->
if (tim == & amp;htim2)
{<!-- -->
HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
}
}
// Timing input capture callback function to calculate duty cycle and frequency
void HAL_TIM_IC_CaptureCallback(TIM_HandleTypeDef *htim)
{<!-- -->
if (htim->Instance == TIM1)
{<!-- -->
if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_1)
{<!-- -->
Cap_val1 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_1);
}
if (htim->Channel == HAL_TIM_ACTIVE_CHANNEL_2)
{<!-- -->
Cap_val2 = HAL_TIM_ReadCapturedValue(htim, TIM_CHANNEL_2);
Duty = 100 - (float)Cap_val2 / (float)Cap_val1 * 100;
Frequency = 0.001 * Cap_val1;
}
}
}
Run results
4. Summary
By completing this assignment, I gained an in-depth understanding of STM32 timer principles and PWM generation methods. From using a timer channel to control the basic operation of LED, to using PWM mode to achieve the breathing light effect, to capturing the period and pulse width of the PWM signal and outputting it through the serial port, I have accumulated a wealth of experience and skills.
This assignment made me familiar with the configuration and operation of the STM32 timer. I also learned how to use the Keil virtual oscilloscope to observe the PWM waveform, which was very helpful during the debugging process. Best of all, I can now control LEDs and other external devices via timers and be able to capture and process the signals generated by these devices.