❶ C語言中定義一個結構體如何在不同的.C文件中使用。
struct
node{
int
a;
int
b;
}
這樣就定義了復一個結構制體類型node,它有兩個int類型的成員,分別是a和b,定義變數是用
struct
node
st_a;
這樣的形式.(例如,上式就定義了一個名為st_a的結構體變數)
❷ 求51單片機超聲波避障程序
這是一個超聲波避障小車的源程序，可以參考下，用的89C52單片機，舵機控制轉角避障。
#include<AT89x51.H>
#include <intrins.h>
#define Sevro_moto_pwm P2_7 //接舵機信號端輸入PWM信號調節速度
#define ECHO P2_4 //超聲波介面定義
#define TRIG P2_5 //超聲波介面定義
#define Left_moto_go {P1_0=1,P1_1=0,P1_2=1,P1_3=0;} //左邊兩個電機向前走
#define Left_moto_back {P1_0=0,P1_1=1,P1_2=0,P1_3=1;} //左邊兩個電機向後轉
#define Left_moto_Stop {P1_0=0,P1_1=0,P1_2=0,P1_3=0;} //左邊兩個電機停轉
#define Right_moto_go {P1_4=1,P1_5=0,P1_6=1,P1_7=0;} //右邊兩個電機向前走
#define Right_moto_back {P1_4=0,P1_5=1,P1_6=0,P1_7=1;} //右邊兩個電機向前走
#define Right_moto_Stop {P1_4=0,P1_5=0,P1_6=0,P1_7=0;} //右邊兩個電機停轉
unsigned char const discode[] ={ 0xC0,0xF9,0xA4,0xB0,0x99,0x92,0x82,0xF8,0x80,0x90,0xBF,0xff/*-*/};
unsigned char const positon[3]={ 0xfe,0xfd,0xfb};
unsigned char disbuff[4] ={ 0,0,0,0,};
unsigned char posit=0;
unsigned char pwm_val_left = 0;//變數定義
unsigned char push_val_left =14;//舵機歸中，產生約，1.5MS 信號
unsigned long S=0;
unsigned long S1=0;
unsigned long S2=0;
unsigned long S3=0;
unsigned long S4=0;
unsigned int time=0; //時間變數
unsigned int timer=0; //延時基準變數
unsigned char timer1=0; //掃描時間變數
/************************************************************************/
void delay(unsigned int k) //延時函數
{
unsigned int x,y;
for(x=0;x<k;x++)
for(y=0;y<2000;y++);
}
/************************************************************************/
void Display(void) //掃描數碼管
{
if(posit==0)
{P0=(discode[disbuff[posit]])&0x7f;}//產生點
else
{P0=discode[disbuff[posit]];} if(posit==0)
{ P2_1=0;P2_2=1;P2_3=1;}
if(posit==1)
{P2_1=1;P2_2=0;P2_3=1;}
if(posit==2)
{P2_1=1;P2_2=1;P2_3=0;}
if(++posit>=3)
posit=0;
}
/************************************************************************/
void StartMole() //啟動測距信號
{
TRIG=1;
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
_nop_();
TRIG=0;
}
/***************************************************/
void Conut(void) //計算距離
{
while(!ECHO); //當RX為零時等待
TR0=1; //開啟計數
while(ECHO); //當RX為1計數並等待
TR0=0; //關閉計數
time=TH0*256+TL0; //讀取脈寬長度
TH0=0;
TL0=0;
S=(time*1.7)/100; //算出來是CM
disbuff[0]=S%1000/100; //更新顯示
disbuff[1]=S%1000%100/10;
disbuff[2]=S%1000%10 %10;
}
/************************************************************************/
//前速前進
void run(void)
{
Left_moto_go ; //左電機往前走
Right_moto_go ; //右電機往前走
}
/************************************************************************/
//前速後退
void backrun(void)
{
Left_moto_back ; //左電機往前走
Right_moto_back ; //右電機往前走
}
/************************************************************************/
//左轉
void leftrun(void)
{
Left_moto_back ; //左電機往前走
Right_moto_go ; //右電機往前走
}
/************************************************************************/
//右轉
void rightrun(void)
{
Left_moto_go ; //左電機往前走
Right_moto_back ; //右電機往前走
}
/************************************************************************/
//STOP
void stoprun(void)
{
Left_moto_Stop ; //左電機停走
Right_moto_Stop ; //右電機停走
}
/************************************************************************/
void COMM( void )
{
push_val_left=5; //舵機向左轉90度
timer=0;
while(timer<=4000); //延時400MS讓舵機轉到其位置
StartMole(); //啟動超聲波測距
Conut(); //計算距離
S2=S;
push_val_left=23; //舵機向右轉90度
timer=0;
while(timer<=4000); //延時400MS讓舵機轉到其位置
StartMole(); //啟動超聲波測距
Conut(); //計算距離
S4=S;
push_val_left=14; //舵機歸中
timer=0;
while(timer<=4000); //延時400MS讓舵機轉到其位置 StartMole(); //啟動超聲波測距
Conut(); //計算距離
S1=S; if((S2<20)||(S4<20)) //只要左右各有距離小於20CM小車後退
{
backrun(); //後退
timer=0;
while(timer<=4000);
}
if(S2>S4)
{
rightrun(); //車的左邊比車的右邊距離小 右轉
timer=0;
while(timer<=4000);
}
else
{
leftrun(); //車的左邊比車的右邊距離大 左轉
timer=0;
while(timer<=4000);
}
} /************************************************************************/
/* PWM調制電機轉速 */
/************************************************************************/
/* 左電機調速 */
/*調節push_val_left的值改變電機轉速,占空比 */
void pwm_Servomoto(void)
{
if(pwm_val_left<=push_val_left)
Sevro_moto_pwm=1;
else
Sevro_moto_pwm=0;
if(pwm_val_left>=200)
pwm_val_left=0;
}
/***************************************************/
///*TIMER1中斷服務子函數產生PWM信號*/
void time1()interrupt 3 using 2
{
TH1=(65536-100)/256; //100US定時
TL1=(65536-100)%256;
timer++; //定時器100US為准。在這個基礎上延時
pwm_val_left++;
pwm_Servomoto(); timer1++; //2MS掃一次數碼管
if(timer1>=20)
{
timer1=0;
Display();
}
}
/***************************************************/
///*TIMER0中斷服務子函數產生PWM信號*/
void timer0()interrupt 1 using 0
{
} /***************************************************/ void main(void)
{ TMOD=0X11;
TH1=(65536-100)/256; //100US定時
TL1=(65536-100)%256;
TH0=0;
TL0=0;
TR1= 1;
ET1= 1;
ET0= 1;
EA = 1; delay(100);
push_val_left=14; //舵機歸中
while(1) /*無限循環*/
{ if(timer>=1000) //100MS檢測啟動檢測一次
{
timer=0;
StartMole(); //啟動檢測
Conut(); //計算距離
if(S<30) //距離小於20CM
{
stoprun(); //小車停止
COMM(); //方向函數
}
else
if(S>30) //距離大於，30CM往前走
run();
}
}
}
/**************************************************************************/
下面是頭文件：
頭文件（一）
/*--------------------------------------------------------------------------
AT89X51.H Header file for the low voltage Flash Atmel AT89C51 and AT89LV51.
Copyright (c) 1988-2002 Keil Elektronik GmbH and Keil Software, Inc.
All rights reserved.
--------------------------------------------------------------------------*/
#ifndef __AT89X51_H__
#define __AT89X51_H__
/*------------------------------------------------
Byte Registers
------------------------------------------------*/
sfr P0 = 0x80;
sfr SP = 0x81;
sfr DPL = 0x82;
sfr DPH = 0x83;
sfr PCON = 0x87;
sfr TCON = 0x88;
sfr TMOD = 0x89;
sfr TL0 = 0x8A;
sfr TL1 = 0x8B;
sfr TH0 = 0x8C;
sfr TH1 = 0x8D;
sfr P1 = 0x90;
sfr SCON = 0x98;
sfr SBUF = 0x99;
sfr P2 = 0xA0;
sfr IE = 0xA8;
sfr P3 = 0xB0;
sfr IP = 0xB8;
sfr PSW = 0xD0;
sfr ACC = 0xE0;
sfr B = 0xF0;
/*------------------------------------------------
P0 Bit Registers
------------------------------------------------*/
sbit P0_0 = 0x80;
sbit P0_1 = 0x81;
sbit P0_2 = 0x82;
sbit P0_3 = 0x83;
sbit P0_4 = 0x84;
sbit P0_5 = 0x85;
sbit P0_6 = 0x86;
sbit P0_7 = 0x87;
/*------------------------------------------------
PCON Bit Values
------------------------------------------------*/
#define IDL_ 0x01
#define STOP_ 0x02
#define PD_ 0x02 /* Alternate definition */
#define GF0_ 0x04
#define GF1_ 0x08 #define SMOD_ 0x80 /
*------------------------------------------------
TCON Bit Registers
------------------------------------------------*/
sbit IT0 = 0x88;
sbit IE0 = 0x89;
sbit IT1 = 0x8A;
sbit IE1 = 0x8B;
sbit TR0 = 0x8C;
sbit TF0 = 0x8D;
sbit TR1 = 0x8E;
sbit TF1 = 0x8F;
/*------------------------------------------------
TMOD Bit Values
------------------------------------------------*/
#define T0_M0_ 0x01
#define T0_M1_ 0x02
#define T0_CT_ 0x04
#define T0_GATE_ 0x08
#define T1_M0_ 0x10
#define T1_M1_ 0x20
#define T1_CT_ 0x40
#define T1_GATE_ 0x80
#define T1_MASK_ 0xF0
#define T0_MASK_ 0x0F
/*------------------------------------------------
P1 Bit Registers
------------------------------------------------*/
sbit P1_0 = 0x90;
sbit P1_1 = 0x91;
sbit P1_2 = 0x92;
sbit P1_3 = 0x93;
sbit P1_4 = 0x94;
sbit P1_5 = 0x95;
sbit P1_6 = 0x96;
sbit P1_7 = 0x97; /
*------------------------------------------------
SCON Bit Registers
------------------------------------------------*/
sbit RI = 0x98;
sbit TI = 0x99;
sbit RB8 = 0x9A;
sbit TB8 = 0x9B;
sbit REN = 0x9C;
sbit SM2 = 0x9D;
sbit SM1 = 0x9E;
sbit SM0 = 0x9F;
/*------------------------------------------------
P2 Bit Registers
------------------------------------------------*/
sbit P2_0 = 0xA0;
sbit P2_1 = 0xA1;
sbit P2_2 = 0xA2;
sbit P2_3 = 0xA3;
sbit P2_4 = 0xA4;
sbit P2_5 = 0xA5;
sbit P2_6 = 0xA6;
sbit P2_7 = 0xA7;
/*------------------------------------------------
IE Bit Registers
------------------------------------------------*/
sbit EX0 = 0xA8; /* 1=Enable External interrupt 0 */
sbit ET0 = 0xA9; /* 1=Enable Timer 0 interrupt */
sbit EX1 = 0xAA; /* 1=Enable External interrupt 1 */
sbit ET1 = 0xAB; /* 1=Enable Timer 1 interrupt */
sbit ES = 0xAC; /* 1=Enable Serial port interrupt */
sbit ET2 = 0xAD; /* 1=Enable Timer 2 interrupt */ sbit EA = 0xAF; /* 0=Disable all interrupts */
/*------------------------------------------------
P3 Bit Registers (Mnemonics & Ports)
------------------------------------------------*/
sbit P3_0 = 0xB0;
sbit P3_1 = 0xB1;
sbit P3_2 = 0xB2;
sbit P3_3 = 0xB3;
sbit P3_4 = 0xB4;
sbit P3_5 = 0xB5;
sbit P3_6 = 0xB6;
sbit P3_7 = 0xB7; sbit RXD = 0xB0; /* Serial data input */
sbit TXD = 0xB1; /* Serial data output */
sbit INT0 = 0xB2; /* External interrupt 0 */
sbit INT1 = 0xB3; /* External interrupt 1 */
sbit T0 = 0xB4; /* Timer 0 external input */
sbit T1 = 0xB5; /* Timer 1 external input */
sbit WR = 0xB6; /* External data memory write strobe */
sbit RD = 0xB7; /* External data memory read strobe */
/*------------------------------------------------
IP Bit Registers
------------------------------------------------*/
sbit PX0 = 0xB8;
sbit PT0 = 0xB9;
sbit PX1 = 0xBA;
sbit PT1 = 0xBB;
sbit PS = 0xBC;
sbit PT2 = 0xBD;
/*------------------------------------------------
PSW Bit Registers
------------------------------------------------*/
sbit P = 0xD0;
sbit FL = 0xD1;
sbit OV = 0xD2;
sbit RS0 = 0xD3;
sbit RS1 = 0xD4;
sbit F0 = 0xD5;
sbit AC = 0xD6;
sbit CY = 0xD7;
/*------------------------------------------------
Interrupt Vectors:
Interrupt Address = (Number * 8) + 3
------------------------------------------------*/
#define IE0_VECTOR 0 /* 0x03 External Interrupt 0 */
#define TF0_VECTOR 1 /* 0x0B Timer 0 */
#define IE1_VECTOR 2 /* 0x13 External Interrupt 1 */
#define TF1_VECTOR 3 /* 0x1B Timer 1 */
#define SIO_VECTOR 4 /* 0x23 Serial port */ #endif
頭文件（二）
/*--------------------------------------------------------------------------
INTRINS.H Intrinsic functions for C51.
Copyright (c) 1988-2002 Keil Elektronik GmbH and Keil Software, Inc.
All rights reserved.
--------------------------------------------------------------------------*/
#ifndef __INTRINS_H__
#define __INTRINS_H__ extern void _nop_ (void);
extern bit _testbit_ (bit);
extern unsigned char _cror_ (unsigned char, unsigned char);
extern unsigned int _iror_ (unsigned int, unsigned char);
extern unsigned long _lror_ (unsigned long, unsigned char);
extern unsigned char _crol_ (unsigned char, unsigned char);
extern unsigned int _irol_ (unsigned int, unsigned char);
extern unsigned long _lrol_ (unsigned long, unsigned char);
extern unsigned char _chkfloat_(float); #endif