Bicycle speed and distance measurement program based on 51 single chip microcomputer

The actual picture is as follows:

The circuit diagram is as follows:

The microcontroller source program is as follows:
#include
#include
#define CIRCLE 2.0 //Macro definition of the circumference of the wheel (this should be set according to the actual wheel)
sbit Signal = P1^0; //The Signal here represents the signal pin of the Hall sensor
int m_second=0; //Define variable m_second to record time (in milliseconds)
float speed=0.0 ; //Define speed variable
float length=0.0 ;//Define distance variable
void main()
{
        lcd_init(); //Initialize LCD function
        TMOD = 0x01; //Turn on timer 0, and set its working mode to 16-bit timing mode.
        TH0=(65536-10000)/ 256;
        TL0=(65536-10000)% 256; //Set the initial value of the timer so that it interrupts every 10ms
        EA = 1; //Allow total interrupt
        ET0 = 1; //Allow timer 0 terminal
        TR0 = 1; //Start timer 0
while(1) //Large loop
{
    while(Signal); //Wait for the Hall sensor signal line to be pulled low;
        speed = CIRCLE *1000/ m_second ; //Calculate speed.
        m_second = 0; //Reset the timer
        length+=CIRCLE ; //Distance plus one wheel cycle
                        //First line, display speed
        lcd_pos(0x00); //Set the LCD writing position to the first line and the first grid
        lcd_wdat('S');
        lcd_wdat('p');
        lcd_wdat('e');
        lcd_wdat('e');
        lcd_wdat('d');
        lcd_wdat(':');
        lcd_wdat((int)speed/10+0x30); //Display the integer part of the speed
        lcd_wdat((int)speed%10+0x30);
        lcd_wdat('.');
        lcd_wdat((int)(speed*10)%10+0x30 ); //Display the first decimal place of the speed lcd_wdat
        ('m');
        lcd_wdat('/');
        lcd_wdat('s');
         
                        //The second line, display mileage
        lcd_pos(0x40); //Set the writing position of the LCD to the first grid of the second line
        lcd_wdat('L');
        lcd_wdat('e')
        ;
        lcd_wdat('n'); lcd_wdat('g');
        lcd_wdat('t')
        ; lcd_wdat('h');
        lcd_wdat(':');
        lcd_wdat((int)length /10000+0x30); //Display the ten thousandth place of mileage;
        lcd_wdat((int)length %10000/1000+0x30);//Display the thousandth place of mileage;
        lcd_wdat((int)length %1000/100+0x30); //Display the hundredth place of mileage;
        lcd_wdat((int)length %100/10+0x30); //Display the tens digit of mileage;
        lcd_wdat((int)length %10+0x30); //Display the ones digit of mileage;
        lcd_wdat('m');
        while(!Signal);
}

}
void timer0_intt() interrupt 1 //
{
        TH0=(65536-10000)/ 256;
        TL0=(65536-10000)% 256; //Set the initial value of the timer so that it interrupts every 10ms
        m_second += 10; //Because the interrupt occurs every 10 milliseconds, 10 is added each time here;
}
#include
#include

/*********************************************************************************
Function:LCD delay subroutine
Entry parameter:ms
Exit parameter:
*********************************************************************************/
static void delay(unsigned char ms)
{
        unsigned char i;
        while(ms--)
                {
                for(i = 0; i< 5; i++);
                }
}

/********************************************************************************
Function: Test LCD busy state
Entry parameter:
Exit parameter: result
*****************************************************************************/
static bit lcd_bz()
{
        bit result;
        rs = 0;
        rw = 1;
        ep = 1;
        delay(5);
        result = (bit)(P0 & 0x80);
        ep = 0;
        return result;
}

/*****************************************************************************
Function: Write instruction data to LCD Subroutine
Entry parameter: cmd
Exit parameter:
*****************************************************************************/
static void lcd_wcmd(unsigned char cmd)
{
        while(lcd_bz()); //Judge whether LCD is busy
                rs = 0;
                rw = 0;
                ep = 0;
                delay(5);
                P0 = cmd;
                        delay(5);
                ep = 1;
                        delay(5);
                ep = 0;
}

/********************************************************************************
Function: Set display position Subroutine
entry parameter: pos
Exit parameter:
*****************************************************************************/
void lcd_pos(unsigned char pos)
{
        lcd_wcmd(pos | 0x80);
}

/*********************************************************************************
Function: Write display data to LCD Subroutine
entry parameter: dat
Exit parameter:
*****************************************************************************/
void lcd_wdat(unsigned char dat)
{
        while(lcd_bz()); //Judge whether LCD is busy
                rs = 1;
                rw = 0;
                ep = 0;
                P0 = dat;
                        delay(5);
                ep = 1;
                        delay(5);
                ep = 0;
}

/********************************************************************************
Function: LCD initialization subroutine
entry parameter:
exit parameter:
*****************************************************************************/
void lcd_init()
{
        lcd_wcmd(0x38);
        delay(100);
        lcd_wcmd(0x0c);
        delay(100);
        lcd_wcmd(0x06);
        delay(100);
        lcd_wcmd(0x01);
        delay(100);
}
/********************************************************************************
Function: LCD writes an integer data
entry parameter: int x
*****************************************************************************/
void lcd_write_int(unsigned int x)  
{
        unsigned char x1,x2,x3,x4,x5;
        x1 = x/10000;
        x2=x%10000/1000;
        x3=x%1000/100;
        x4=x%100/10;
        x5=x%10;
        lcd_wdat(x1+0x30);
        lcd_wdat(x2+0x30);
        lcd_wdat(x3+0x30);
        lcd_wdat(x4+0x30);
        lcd_wdat(x5+0x30);
}
#ifndef __STAR1602_H__
#define __STAR1602_H__

sbit rs= P2^6; //
sbit rw = P2^5; //     
sbit ep = P2^7; //


void lcd_init(); //LCD initialization function
void lcd_pos(unsigned char pos); //LCD display position setting function
void lcd_wdat(unsigned char dat); //LCD writes characters
void lcd_write_int(unsigned int x); //LCD displays an integer variable