Blue Bridge Cup SCM module code (LED) (code + comments)

#include "STC15F2K60S2.H"
/* The header file ; comparison reg52.h Omit sbit The use of equal functions , It is more suitable for single chip computers in competitions , Readers can use STC-ISP Installation */

typedef unsigned int u16;
typedef unsigned char u8;.
/* Redefine the variable name , Convenient programming ; Unsigned integer is 2 byte , from 16 position 2 Composition of binary system , The unsigned character is 1 byte , from 8 Bit binary composition */

void close()
{
  P0=0;
/*P0=0000 0000*/
  P2=P2&0X1F|0XA0;
/* Use binary and or operations , We will clear the top three first , And then set the senior three to 101,101 The decimal system of is 5, So the decoder 74HC138 take Y5 Turn to low level , NOR gate calculation Y5C=0+0=0 Non - =1, Open the latch ,P0=0 The signal is transmitted to the right , because ULN2003 There is a non gate inside , therefore BUZZER The input is VCC, The buzzer doesn't sound */
  P2=P2&0X1F;
/* Enable the decoder to Y0 Set to low level , This single chip microcomputer Y0 In the air , So it will not affect the application of any other program , Play a protective role , The next three lines are similar , Do not repeat */
  P0=0XFF;
  P2=P2&0X1F|0X80;
  P2=P2&0X1F;
}
/* This function turns off peripheral functions , When the MCU is reset , Default LED All the lights are on , Buzzer ring , So the peripheral function is closed to extinguish LED, Turn off the buzzer , Achieve the user's desired initialization state */

void lighten(u8 led)
{
  P0=~led;
/* In the schematic diagram , According to the unidirectional conductivity of the diode ,P0 One of them is 0 when , Corresponding LED Light on ; Negation makes the input P0 Some one is 1 when , Corresponding light is on , Make programming easier to understand , Of course, it is also possible not to take the opposite */
  P2=P2&0X1F|0X8F;
  P2=P2&0X1F;
}
/* This function is lit LED function */

void delay(u8 num)
{
  u16 i;
  while(num--)
  for(i=0;i<=1000;i++);
} 
/* The time delay function , This section is used to extend the time of each state ; The function run time can be determined by the current crystal oscillator 、 Instruction type and number of cycles , But it is not necessary to ,STC-ISP There is already a computing function , And there is a timer module in the MCU , This function is used here only to show the phenomenon */

void main()
{
  u8 num,time;
  close();
  while(1)
  {
    for(num=1;num<=5;num++)
/* By changing num It's not hard to see ： The delay function changes in multiples of time ,num The change is the time when the light is on and off in each cycle , But even if delay Time has multiplied , Still too fast for the human eye , therefore num Different , What we feel is the brightness of the light */
	  for(time=0;time<100;time++)
/* loop 100 The second is to ensure that the time for each brightness is not too short , Easy to observe */
	  {
	    lighten(0);
	    delay(5-num);
		lighten(0xff);
		delay(num);
      } 
  }
}
/* This code achieves the effect of gradient brightness , Readers can improve it , Achieve a gorgeous effect .*/

Official schematic diagram , The download address of the user manual is as follows ：

link ：https://pan.baidu.com/s/1y8lRYHxLKojL4_r0PZPYRw 
Extraction code ：19so

Note cannot insert picture , Relevant information readers themselves look for in the folder .

Study notes for undergraduate students of Nanjing University of Information Engineering , For your reference .

If there is a mistake , contact QQ3182097183.