Practical analysis of 8051 microcontroller (taking STC89C52RC as an example) | 02 - LED flashes with a delay of about 5 seconds

The code is modified as follows:

#include "reg52.h" //This file defines some special function registers of the microcontroller

typedef unsigned int u16;   //declare and define the data type

typedef unsigned char u8;

sbit led=P2^2; //Define the P2.2 port of the microcontroller as led

/*******************************************************************************

* Function name: delay

* Function    : Delay function, when i=1, the delay is about 10us

*******************************************************************************/

void delay(u16 i)

{

while(i--);

}

/*******************************************************************************

 * Function name: main

 * Function : Main function

 * Input: None

 * Output    : None

*******************************************************************************/

void main()

{

while(1)

{

led=0;

delay(50000); //About 450ms delay

led=1;

delay(50000); //About 450ms delay

}

}

Typedef is used in the code to declare and define data types. This is a syntax of C language, which is easy to understand. Here, u16 is used instead of unsigned int. In an 8-bit microcontroller, 16-bit data can be represented, which can represent numbers from 0 to 65535 (2^16-1). Similarly, u8 is used instead of unsigned char.

Add a delay function, which implements a self-decrementing infinite loop to achieve the purpose of delay. We will know later that this method is not recommended, but here it can roughly achieve a delay of about 5s for the LED to flash.