STM32 GPIO - Flowing Light Routine Learning Summary

By controlling LED lights, you can become familiar with STM32's memory structure, address mapping, clock tree, library files, library utilization methods, and development project steps, and establish STM32 development ideas.

This is the first project I have built. Since it involves a wide range of areas and the knowledge points are scattered, I will make a summary here.

1) To control the LED light, you need to use the GPIO peripheral.

GPIO (General-Purpose I/O): I/O pins can be set by software to various functions, such as input or output. Controlling the LED light is achieved by controlling the level of the I/O pins of the STM32 chip.

2) Understand the functions of the GPIO peripheral and how to use it.

GPIO pins are divided into different groups: GPIOA, GPIOB, ..., GPIOG. Each group of ports is divided into 16 different pins from 0 to 15. For different chip models, the number of port groups and pins is different.

Function View Reference Manual

3) Get the address mapping of GPIO and know the bus APB2 on which it is mounted.

4) Understand the encapsulation of registers in the ST official library.

5) Understand the clock tree and check the clock source of GPIOC, which is PCLK2.

6) Include the used header files stm32f10x_gpio.h and stm32f10x_rcc.h in the stm32f10x_conf.h file.

7) Add led.c and led.h user files based on the project template.

8) Write the driver initialization function LED_GPIO_Config().

9) Turn on the peripheral GPIOC clock and analyze whether the default clock frequency of Sysclk=71MHz configured by the SystemInit() function meets the project requirements.

10) Define and fill the initialization structure GPIO_InitStructure according to the control requirements, and write appropriate parameters to the corresponding structure members.

11) Call the initialization function GPIO_Init() to initialize GPIOC.

12) Write the corresponding led.h header file.

13) Write the main application.

14) Debug the program and complete.

The project I built:

/*led.h*/

#ifndef __LED_H

#define __LED_H

#include "stm32f10x.h"

#define ON  0

#define OFF 1

#define LED1(a) if(a) \

                 GPIO_SetBits(GPIOD,GPIO_Pin_3);\

else   \

GPIO_ResetBits(GPIOD,GPIO_Pin_3)

#define LED2(a) if(a) \

                 GPIO_SetBits(GPIOD,GPIO_Pin_6);\

else   \

GPIO_ResetBits(GPIOD,GPIO_Pin_6)

#define LED3(a) if(a) \

                 GPIO_SetBits(GPIOB,GPIO_Pin_5);\

else   \

GPIO_ResetBits(GPIOB,GPIO_Pin_5)

void LED_GPIO_Config(void);

#endif /*__LED_H*/

/*led.c*/

#include "led.h"

/*Configure the I/O port used by the LED*/

void LED_GPIO_Config(void)

{

/*Define a GPIO_InitTypeDef type structure*/

   GPIO_InitTypeDef GPIO_InitStructure;

/*Turn on the peripheral clock of GPIOC*/

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB,ENABLE);

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD,ENABLE);

/*Select the GPIO pin to control*/

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3 | GPIO_Pin_6 | GPIO_Pin_5;

/*Set pin mode to general push-pull output*/

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

/*Set the pin rate to 50MHz*/

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

/*Call library function to initialize GPIOB, GPIOD*/

GPIO_Init(GPIOB,&GPIO_InitStructure);

GPIO_Init(GPIOD,&GPIO_InitStructure);

/*Turn off all LED lights*/

GPIO_SetBits(GPIOB,GPIO_Pin_5); //Pins 3, 6, and 5 output high level and turn off the three LED lights

GPIO_SetBits(GPIOD,GPIO_Pin_3|GPIO_Pin_6);

}

/*main.c*/

#include "stm32f10x.h"

#include "led.h"

void Delay(__IO u32 nCount);

int main (void)

{

SystemInit() ; //Set the system clock SYSCLK

LED_GPIO_Config();

   while(1)

{

      LED1(ON); //light up

 Delay(0x0FFFEF);

 LED1(OFF);

 LED2(ON);  

 Delay(0x0FFFEF);

 LED2(OFF);

 LED3(ON);  

 Delay(0x0FFFEF);

 LED3(OFF);

  }

The above code runs in the STM32 class. The following is a recommended example for comparison to find out your own shortcomings.

/*example*/

#include"stm32f10x.h"

#define ON           1

#define OFF          0

#define DELAY_TIME   0x3FFFFF

enum 

{

        LED1 = 0,

LED2,

LED3,

MAX_LED,

};

typedef struct led_gpio_s

{

int num; /* LED number*/

GPIO_TypeDef *group; /* Which group is the GPIO used by the LED: GPIOB or GPIOD */

        uint16_t pin; /* Which pin in the GPIO group is used by the LED: GPIO_Pin_x */

} led_gpio_t;

led_gpio_t        leds_gpio[MAX_LED] =

{

{LED1, GPIOB, GPIO_Pin_5}, /* GPB5 for LED1 */

{LED2, GPIOD, GPIO_Pin_6}, /* GPD6 for LED2 */

{LED3, GPIOD, GPIO_Pin_3}, /* LED3 use GPD3 */

};

void init_led_gpio(void)

{

int                i;

GPIO_InitTypeDef   GPIO_InitStructure;

/* Enable the clock of PB and PD group GPIO*/

  RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOD , ENABLE);

/*Set PB5(LED1), PD6(LED2), PD3(LED3) to GPIO output push-to-disable mode, port line flip speed is 50MHz */

for(i=0; i

{

/*Set PB5 (LED1) to GPIO output push-to-disable mode, port line flip speed is 50MHz */

GPIO_InitStructure.GPIO_Pin = leds_gpio[i].pin;     

GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;

GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;

GPIO_Init(leds_gpio[i].group, &GPIO_InitStructure);

  }

}

void turn_led(int which, int cmd)

{

         if(which<0 || which> MAX_LED )

return;

if(OFF == cmd)

GPIO_ResetBits(leds_gpio[which].group, leds_gpio[which].pin);

else

GPIO_SetBits(leds_gpio[which].group, leds_gpio[which].pin);

}

void Delay(__IO uint32_t nCount)

{

   for(; nCount != 0; nCount--) ;

}

int main(void)

{

/* Initialize system clock */

        SystemInit();

/* Initialize the GPIO pins of each LED*/

init_led_gpio();

  while(1)

  {

 /* Turn on LED1 and turn off LED2 and LED3*/

turn_led(LED1, ON);

 turn_led(LED2, OFF);

turn_led(LED3, OFF);

 Delay(DELAY_TIME);

 /* Turn on LED2 and turn off LED1 and LED3*/

turn_led(LED2, ON);

 turn_led(LED1, OFF);

turn_led(LED3, OFF);

 Delay(DELAY_TIME);

 /* Turn on LED3 and turn off LED1 and LED2*/

turn_led(LED3, ON);

 turn_led(LED2, OFF);

turn_led(LED1, OFF);

 Delay(DELAY_TIME);

  }

}