基于51单片机的超声波测距项目源码.zip

/** * @file main.c * @author greedyhao (hao_ke@163.com) * @brief * @version 0.1 * @date 2019-11-07 * * @copyright Copyright (c) 2019 * */ #include <STC12C5A60S2.H> #include <math.h> /* macro */ #define sound_velocity 34300 /* sound velocity in cm per second */ #define period_in_us pow(10,-6) #define Clock_period 1.085*period_in_us /* period for clock cycle of 8051*/ #define SEG_PORT P1 sbit SEG_BIT0 = P2^3; sbit SEG_BIT1 = P2^2; sbit SEG_BIT2 = P2^1; sbit SEG_BIT3 = P2^0; sbit BEEP_PIN = P2^4; sbit TRIG_PIN = P2^5; sbit ECHO_PIN = P2^6; /* user define */ code unsigned char seg_table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x88,0x83,0xc6,0xa1,0x86,0x8e}; unsigned int num = 0; /* the number displayed on 7-segment */ unsigned char time_out = 0; /* ECHO port */ unsigned char beep_frq = 0; /* counting the beep pin toggle time */ unsigned char beep_lv = 0; /* level of rapid (0-4) */ unsigned char beep_flag = 0; /* status of beep 0: no work 1: rapid beep 2: long beep */ /* static func */ /* public func */ void init_timer(void); void delay_10us(void); void delay_ms(unsigned char n); void seg_dis(unsigned int num); void uw_sen_start(void); /* ------------- main ---------------- */ void main(void){ unsigned long tmp = 0; float distance_measurement, value; P2 = 0x0f; P2M1 = 0x40; //0100 0000 P2M0 = 0x30; //0011 0000 init_timer(); while (1) { uw_sen_start(); time_out = 0; while (ECHO_PIN == 0 && time_out < 2); time_out = 0; TR0 = 1; ET1 = 0; while (ECHO_PIN == 1); TR0 = 0; /* calculate distance using timer */ value = Clock_period * sound_velocity; distance_measurement = (TL0|(TH0<<8)); /* read timer register for time count */ distance_measurement = (distance_measurement*value)/2.0; /* find distance(in cm) */ num = (int)(distance_measurement*10)%10000; if (num <= 800 && num > 300) { beep_flag = 1; beep_lv = (num - 300)/100; /* (x - 300)/500*5 (level 5) */ } else if (num <= 300) beep_flag = 2; else beep_flag = 0; ET1 = 1; delay_ms(100); } } /* ------------ delay --------------- */ static void _delay_1ms(void) //误差 -0.651041666667us { unsigned char a,b; for(b=4;b>0;b--) for(a=113;a>0;a--); } static void _delay_10ms(void) //@11.0592MHz { unsigned char a,b; for(b=151;b>0;b--) for(a=29;a>0;a--); } void delay_ms(unsigned char n) //误差 -0.000000000002us { do { _delay_1ms(); } while (--n); } /* ------------ ultrasonic --------------- */ void init_timer(void) { TMOD = 0x11; TF0 = 0; TR0 = 0; TH1 = 0xB8; /* 20ms */ TL1 = 0x00; EA = 1; ET1 = 1; TR1 = 1; } void delay_10us(void) { TL0=0xF7; TH0=0xFF; TR0=1; while (TF0!=1); TR0=0; TF0=0; } /** * @brief ultrasonic sensor start working * */ void uw_sen_start(void) { TRIG_PIN = 1; delay_10us(); TRIG_PIN = 0; } /* ------------ segment --------------- */ /** * @brief display number on 7-segment * * @param num number format: xxx.x * @note num must less than 9999 */ void seg_dis(unsigned int num) { unsigned char _bit0, _bit1, _bit2, _bit3; _bit0 = _bit1 = _bit2 = _bit3 = 0; _bit0 = num % 10; _bit1 = num / 10 % 100; _bit2 = num / 100 % 1000; _bit3 = num / 1000; P2 = P2 | 0x0f; SEG_BIT0 = 0; SEG_PORT = seg_table[_bit0%10]; delay_ms(1); SEG_BIT0 = 1; // SEG_PORT = 0xff; SEG_BIT1 = 0; SEG_PORT = seg_table[_bit1%10]&0x7F; delay_ms(1); SEG_BIT1 = 1; // SEG_PORT = 0xff; SEG_BIT2 = 0; SEG_PORT = seg_table[_bit2%10]; delay_ms(1); SEG_BIT2 = 1; // SEG_PORT = 0xff; SEG_BIT3 = 0; SEG_PORT = seg_table[_bit3%10]; delay_ms(1); SEG_BIT3 = 1; // SEG_PORT = 0xff; } void Timer1Interrupt(void) interrupt 3 { TH1 = 0xB8; /* 20ms */ TL1 = 0x00; seg_dis(num); ++beep_frq; ++time_out; switch (beep_flag) { case 0: BEEP_PIN = 0; break; case 1: switch (beep_lv) { case 0: if (beep_frq >= 1) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; case 1: if (beep_frq >= 5) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; case 2: if (beep_frq >= 10) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; case 3: if (beep_frq >= 15) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; case 4: if (beep_frq >= 20) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; default: if (beep_frq >= 20) {BEEP_PIN = !BEEP_PIN; beep_frq = 0;} break; } break; case 2: BEEP_PIN = 1; break; default: break; } }