STM32 learning record: LED light flashes (register version)

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STM32F103ZE： Punctual atomic elite board , Use register to light up LED

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Preface

The main thing is to be able to use STM3210X The development manual for , Will check the schematic diagram of the board , Understand the concept of bus , Can find registers .
Simply calling the library is not enough , Because it's all encapsulated by others , Want to be an excellent engineer , Must be able to program at the bottom .

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One 、 Refer to the development manual

1. Open the schematic diagram of punctual atomic elite board , seek LED The pin of

You can see ,LED0 and LED1 Respectively in GPIOB5 and GPIOE5 On the pin .

2. open STM32 Chinese Reference Manual , Conduct data inquiry

Have a look first STM32 The system structure of

You can find RCC To control the clock , And GPIOB and GPIOE All by APB2 control

3. Then take a look at RCC Register peripheral APB2 Clock enable register

to glance at APB2 Address offset of

Check it out. GPIOB and GPIOE Bit

You can see ,GPIOB It's No 3 position ,GPIOE It's No 6 position ;

4. View register image , Looking for an address

5. Check the port output data register

6. Check the port configuration low register

All right. ！ That's all for checking the information , It's not hard , Just know how to find registers .

Two 、 Development steps

1. Lighten up LED

The code is as follows （ Shown ）：

RCC Clock address

#include "stm32f10x.h"

int main(void)
{
    
		*(unsigned int *)0x40021018 |=(1<<3);//RCC The address is 0x40021000,APB2 The offset is 18, therefore , open GPIOB Enable clock . towards ←3 position .
	
		*(unsigned int *)0X40010C00 |=((1)<<(4*5));//‘|=’  Set up 1; Configure low level ,*5 Because in 5 On port 
	
		*(unsigned int *)0X40010C0C &=~(1<<5);//‘&=~’  Zero clearing ; Configure port data output 
	
		*(unsigned int *)0x40021018 |=(1<<6);// open GPIOE Enable clock . towards ←6 position .
	
		*(unsigned int *)0x40011800 |=((1)<<(4*5));
	
		*(unsigned int *)0x4001180C &=~(1<<5);
}

Verified , Success will punctual the atomic elite board LED0、LED1 The light is on

2. Give Way LED Light flashing

LED.h

The code is as follows （ Shown ）：

#ifndef __led_H
#define __led_H

void LED_Init(void);

#endif

LED.c

The code is as follows （ Shown ）：

#include "stm32f10x.h"
#include "led.h"

void LED_Init(void)
{
    
		RCC->APB2ENR|=1<<3;//-> Structure pointer ; Can make B
		RCC->APB2ENR|=1<<6;//-> Structure pointer ; Can make E
		/*GPIOB5*/
		GPIOB->CRL&=0xFF0FFFFF;
		GPIOB->CRL|=0x00300000;
		GPIOB->ODR|=1<<5;
		/*GPIOE5*/
		GPIOE->CRL&=0xFF0FFFFF;
		GPIOE->CRL|=0x00300000;
		GPIOE->ODR|=1<<5;
}

main.c

The code is as follows （ Shown ）：

#include "stm32f10x.h"
#include "led.h"
#include "delay.h"

int main(void)
{
    
		delay_init(72);
		LED_Init();
		while(1)
		{
    
				GPIOB->ODR|=1<<5;
				delay_ms(500);
				GPIOB->ODR=~(1<<5);
				delay_ms(500);
				GPIOE->ODR|=1<<5;
				delay_ms(500);
// GPIOB->ODR=~(1<<5);
				GPIOE->ODR=~(1<<5);
				delay_ms(500);
		}
}