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Write it at the front

Before learning , Predecessors always told me to master registers , Yesterday was the first day to officially start studying the board , It starts with library functions , Although I can understand what I'm doing , Always feel like something's missing . Today, my classmate asked me whether you implemented it with library function or configuration register . So I began to study the configuration of registers .

One 、 To configure GPIO register

GPIO The configuration is similar to yesterday's process , Just don't call library functions , Directly related to the setting of the register .

Or yesterday's schematic diagram ：

Or settings PA8 Take an example to illustrate .

1. Can make IO Port clock

The first step in using library functions is to define a GPIO Structural variable , If you configure the register directly, you don't need to define a GPIO Structure variable to assign value , Just assign a value to the register directly . So the first step is to enable the corresponding IO The clock of the port .

// Library function 
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);

Can make IO Port clock , According to yesterday's experience, it should be in RCC Then find the register . Register found , Set according to the data manual OK.

therefore

// register 
RCC->APB2ENR |= (1 << 2);//ENABLE GPIOA CLK

2. To configure PA8 Corresponding parameters of the pin

If you understand it by the small steps subdivided when learning library functions yesterday , All three members of the structure are finished in this step . To set up PA8 Pin , First find the register that controls it .

To set up for 50M Push pull output mode , Therefore, the register is no 3 Position to the first 0 Is it 0011, That is to say 0x03.
However, it should be noted that when setting the control register , You have to clear it first .

GPIOA->CRH &= 0xFFFFFFF0;//CLEAR PA8
GPIOA->CRH |= 0x00000003;//PA8 50M PP

It can be said that the initialization has been completed now .
Just configure other pins like this .

Two 、 Realization of water lamp

1.LED Pin configuration

LED.h

#ifndef __LED_H
#define __LED_H

void LED_GPIO_Config(void);

#endif /* __LED_H */

LED.c

#include "LED.h"


void LED_GPIO_Config(void)
{
    
	//PA8
	RCC->APB2ENR |= (1 << 2);//enable GPIOA CLK
	GPIOA->CRH &= 0xFFFFFFF0;//clear PA8
	GPIOA->CRH |= 0x00000003;//PA8 50M PP
	GPIOA->ODR |= 1<<8;//LED0_OFF
	
	//PB11
	RCC->APB2ENR |= (1 << 3);//enable GPIOB CLK
	GPIOB->CRH &= 0xFFFF0FFF;//clear PB11
	GPIOB->CRH |= 0x00003000;//PB11 50M PP
	GPIOB->ODR |= 1<<11;//LED1_OFF
	
}

2. The main function

#include "stm32f10x.h"
#include "LED.h"
#include "DELAY.h"

int main(void)
{
    	
	LED_GPIO_Config();
	
	while(1)
	{
    
		GPIOA->ODR |=(1<<8);
		GPIOB->ODR &=~(1<<11);
		Delay(0x2fffff);
		
		GPIOA->ODR &=~(1<<8);
		GPIOB->ODR |=(1<<11);
		Delay(0x2fffff);
	}
}

summary

Today, I always want to control from the key LED The lamp starts to master the setting of the register , Overestimate your mastery of registers , So that when the running program can't run normally, I don't know where to check , Because there are so many problems . Finally, just configure it honestly LED The lights start , Slowly master one by one and then correct mistakes , Finally, a water lamp came out , It's a little harvest . Write notes before today's study , The register configuration version of the program that still struggles to add keys , The result is to hit yourself more . That's it today , Go on learning tomorrow , Take your time , After all, it's just chicken , How high can you expect of yourself .