Basic timers

Basic timers1、software-hardware2、Brief principle2.1、Hardware schematic diagram2.2、Physical connection diagram2.3、Principle of control3、Engineering configuration3.1、Tips3.2、Pin configuration4、Main functions4.1、User function4.2、HAL library function parsing5、Experimental phenomenon

This tutorial demonstrates controlling the onboard LED1 and LED2 blinkers on the dev board using a basic timer (TIM6).

1、software-hardware

STM32F103CubeIDE
SSTM32 Robot Development Board
TIM: Chip internal peripherals
LED light: onboard
Type-C cable or ST-Link
Download or simulate the program of the development board

2、Brief principle

2.1、Hardware schematic diagram

2.2、Physical connection diagram

2.3、Principle of control

The GPIO output function is used to control the LED, and the timing function is realized through the basic timer.

GPIO output

By controlling the high and low level of the LED lamp pin to control the color of the LED lamp display.

LED：High level light, low level off

LED（Schematic name）	Control pin	Functions
LED1	PG14	Control LED1 to turn on and off
LED2	PG15	Control LED2 to turn on and off

Basic timers

The timing function of TIM6 on the STM32F103ZET6 development board was used

Timer types	Basic timer
The name of timer	TIM6、TIM7
Number of counter bits	16
Counting mode	incrementally
Predivision coefficient	1-65536
Generating DMA requests	Yes
Capture/compare channels	0
Complementary output	No
Clock frequency	72MHz (Max)
Mount bus	APB1

Time base unit

register	Funciton
The counter register（TIMx_CNT）	The current value of the counter
Predivision register（TIMx_PSC）	Set frequency division coefficient (1-65536)
Automatically reload registers（TIMx_ARR）	The counter counts the boundary and the overloaded value

Timing formula

T (s) = \frac{(A R R + 1) * (P S C + 1)}{T I M_C L K (H z)}

parameters	Meaning
T（s）	Timing time in seconds
ARR	Automatically reload the value
PSC	Predivision coefficient
TIM_CLK	The timer ticks in Hz

Timing time for the project: 10ms

T (s) = \frac{(A R R + 1) * (P S C + 1)}{T I M_C L K (H z)} = \frac{(99 + 1) * (7199 + 1)}{72000000 (H z)} = 0.01 s

3、Engineering configuration

Project Configuration: Prompts for configuration options in the STM32CubeIDE project configuration process

3.1、Tips

Omitted project configuration: New project, chip selection, project configuration, SYS for pin configuration, RCC configuration, clock configuration, and project configuration content

The project configuration part, which is not omitted, is the key point to configure in this tutorial.


xxxxxxxxxx
Please refer to [2. Development environment construction and use: STM32CubeIDE installation and use] to understand how to configure the omitted parts of the project.

3.2、Pin configuration

Configure the specified pin function

You can directly select the corresponding pin number in the pin view, and the corresponding option will appear when the mouse is left clicked

d3d723bc194dac4ec7b14d02d903fcf1

GPIO

Timers

NVIC

Advanced Settings

Generating code

4、Main functions

This section mainly introduces the functional code written by users. Detailed code can be opened by yourself in the project file we provide, and enter the Bsp folder to view the source code.

4.1、User function

HAL_TIM_IRQHandler：The timer interrupt service function

Function prototypes	void HAL_TIM_IRQHandler(TIM_HandleTypeDef *htim)
Functional Description	The timer interrupt service function
Input parameters	htim：Timer handle address
Return value	None
Notes	1. Internally, the function needs to determine the interrupt type and clear the corresponding interrupt flag, and finally call the callback function Define the USE_HAL_IRQ macro to switch between different interrupt handling functions


xxxxxxxxxx
/*
If the HAL library is used, the HAL_TIM_IRQHandler function is invoked to automatically handle timer interrupts.
If the HAL library is not used, the timer update interrupt is checked to see if the interrupt bit is set.
*/
void TIM6_IRQHandler(void)
{
#if USE_HAL_IRQ
  HAL_TIM_IRQHandler(&htim6);//Using HAL_TIM_PeriodElapsedCallback is automatically invoked
#else
  if (__HAL_TIM_GET_FLAG(&htim6, TIM_FLAG_UPDATE) != RESET)//Check if the TIM update interrupt occurred
    {
      if (__HAL_TIM_GET_IT_SOURCE(&htim6, TIM_IT_UPDATE) != RESET) //Check if interrupts for TIM6 are enabled
      {
        __HAL_TIM_CLEAR_IT(&htim6, TIM_IT_UPDATE);//Clearing interrupts
        g_time++;
        if(g_time % 100 == 0)//1s = 100*10ms
         {
             g_time = 1;
             HAL_GPIO_TogglePin(LED1_GPIO_Port,LED1_Pin);
         }
        else if(g_time % 50 == 0)//500ms = 50*10ms
         {
             HAL_GPIO_TogglePin(LED2_GPIO_Port,LED2_Pin);
         }
      }
    }
#endif
}

HAL_TIM_PeriodElapsedCallback：The timer update interrupt callback function

Function prototypes	void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
Functional Description	The timer update interrupt callback function
Input parameters	htim：Timer handle address
Return value	None
Notes	This function is called by HAL_TIM_IRQHandler, which allows you to write specific tasks


xxxxxxxxxx
/*
HAL library internal timer update interrupt callback function
*/
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
     if(htim->Instance==TIM6)
      {
         g_time++;
      }
     if(g_time % 100 == 0)//1s = 100*10ms
     {
         g_time = 1;
         HAL_GPIO_TogglePin(LED1_GPIO_Port,LED1_Pin);
     }
     if(g_time % 50 == 0)//500ms = 50*10ms
     {
         HAL_GPIO_TogglePin(LED2_GPIO_Port,LED2_Pin);
     }
}

4.2、HAL library function parsing

The HAL library functions that were covered in the previous tutorial will not be covered


xxxxxxxxxx
If you want to find the HAL library and LL library function analysis involved in the entire tutorial, you can view the documents in the folder [8. STM32 Manual: STM32F1_HAL Library and LL Library_User Manual]

function：HAL_TIM_Base_Init

Function prototypes	HAL_StatusTypeDef HAL_TIM_Base_Init(TIM_HandleTypeDef *htim)
Functional Description	Initialize the timer base unit
Input parameters	htim：Timer handle address
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT
Notes	This calls the MCU low-level initialization function HAL_TIM_Base_MspInit to set the pins, clocks, and interrupts

function：HAL_TIM_Base_MspInit

Function prototype	void HAL_TIM_Base_MspInit(TIM_HandleTypeDef *htim);
Functional description	Initialize the peripheral clock, GPIO, and NVIC for the timer
Input parameters	htim：Timer handle address
Return value	None

function：HAL_TIM_Base_MspDeInit

Function prototype	void HAL_TIM_Base_MspDeInit(TIM_HandleTypeDef *htim)
Functional description	Uninitialize the timer peripheral clock, GPIO, and NVIC
Input parameters	htim：Timer handle address
Return value	None

function：HAL_TIM_Base_Start_IT

Function prototype	HAL_StatusTypeDef HAL_TIM_Base_Start_IT(TIM_HandleTypeDef *htim)
Functional description	Starts the timer and enables the interrupt function of the timer能
Input parameters	htim：Timer handle address
Return value	HAL status value：HAL_OK、HAL_ERROR、HAL_BUSY、HAL_TIMEOUT
Notes	This function needs to be called by the user to enable and start the update interrupt of the timer

5、Experimental phenomenon

After downloading the program successfully, press the RESET button of the development board to observe the phenomenon of the development board


xxxxxxxxxx
For program download, please refer to [2. Development environment construction and use: program download and simulation]

现象：

LED1：The bright-off time interval is 1 second

LED2：The bright-off time interval is 0.5 seconds


Experimental phenomena can be found in [Basic Timer_Experimental Phenomenon.mp4]