Lecture 4 - explain GPIO_ Write function and related routines

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Preface

I explained the beginnings before GPIO Several functions of , Here is another function , This function operates on all ports

GPIO_Write function , Compared with other functions explained in the previous article , The biggest feature is that it can assign values to multiple ports .

Let's look at the function definition first ：

void GPIO_Write(GPIO_TypeDef* GPIOx, uint16_t PortVal)
{
  /* Check the parameters */
  assert_param(IS_GPIO_ALL_PERIPH(GPIOx));
  
  GPIOx->ODR = PortVal;
}

The first parameter is the same as before , Because it operates on multiple ports , We use GPIOA Take all ports of as an example , First parameter or GPIOA, Focus on the second parameter , See parameter definition ：

  * @param  PortVal: specifies the value to be written to the port output data register.

It means , Specify the value to be written to the port output data register .

With LED Take the running water lamp as an example , With this function, we can directly configure PA0-PA15 16 Ports

Go straight to the code ：

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
int main()
{
	
		RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);// Use RCC Turn on GPIO The clock 
		GPIO_InitTypeDef GPIO_InitStructure;
		GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // Push pull output 
		GPIO_InitStructure.GPIO_Pin = GPIO_Pin_All;// hold 16 All ports are configured as push-pull output  
		//GPIO_Pin_0 | GPIO_Pin_1 | GPIO_Pin_2 ;// Bitwise “ or ” Select multiple ports 
		GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz ;
		GPIO_Init(GPIOA,&GPIO_InitStructure);
	    // Up to the top ,GPIO Initialization complete  
	  while(1)

	  {
		
        GPIO_Write(GPIOA,~0X0001);// Because the low level is on , So bitwise inversion , The first one at this time LED Light others as off 			
		//0000 0000 0000 0001   Corresponding PA0-PA15  16 Ports , Its lowest PA0
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0002);//0000 0000 0000 0010
		Delay_ms(500);
	    GPIO_Write(GPIOA,~0X0004);//0000 0000 0000 0100
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0008);//0000 0000 0000 1000
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0010);//0000 0000 0001 0000
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0020);//0000 0000 0010 0000
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0040);//0000 0000 0100 0000
		Delay_ms(500);
		GPIO_Write(GPIOA,~0X0080);//0000 0000 1000 0000 
		Delay_ms(500);
       
     }
}

It should be noted that , stay GPIO_Init Of middle structure Pin Change to all ports , That is to say GPIO_Pin_All .

In a dead cycle , The second parameter is represented by hexadecimal numbers , Because we choose LED Illuminates for low level , So we take the opposite position , The first one at this time LED Light others as off , The bitwise reverse operation turns on the... On each port in turn LED, Add delay to realize LED Running water lamp .