学习C51过程中常见的错误

1、学习C51过程中常见的错误C语言编程-记录1-15.关键词main-错写mian 警告提示：Build target Target 1assembling STARTUP.A51.compiling K1-K4 控制数码管加减演示.c.linking.* WARNING L16: UNCALLED SEGMENT, IGNORED FOR OVERLAY PROCESS SEGMENT: ?PR?MIAN?K1_K4_控_剖详细齙牍_加减演示* WARNING L1: UNRESOLVED EXTERNAL SYMBOL SYMBOL: MAIN MODULE: D:PROGRAM FILES

2、 (X86)C51LIBC51S.LIB (?C_INIT)* WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL SYMBOL: MAIN MODULE: D:PROGRAM FILES (X86)C51LIBC51S.LIB (?C_INIT) ADDRESS: 0010HProgram Size: data=14.0 xdata=0 code=347creating hex file from K1-K4 控制数码管加减演示.K1-K4 控制数码管加减演示 - 0 Error(s), 3 Warning(s).1-14.全局变量和局部变量，

3、以及变量赋值位置-在循环体中差异#include#include#define uchar unsigned char#define uint unsigned intuchar key_count; /循环子程序，累计变量赋值为0，应设为全局变量。sbit k1=P10;sbit k2=P11;sbit k3=P12;uchar code table_duan=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f; uchar duan=0,10,10,10,10,10,10,10; /控制数码管显示数值void delay(uint i)uch

4、ar a;while(i-) for(a=0;a120;a+);void init()P0=0xff;P2=0x00;P1=0xff; void show_steady() uchar b,wei=0x80;for(b=0;b8)key_count=0;duankey_count=key_count;if(k2=0)/key_count-;if(key_count1)key_count=0;duankey_count=10;key_count-;if(k3=0)duan0=0;for(i=0;i8;i+)duani=10;key_count=0; void main()init();key_c

5、ount=0;while(1)show_steady();P1=0xff;key_select();while(P1!=0xff)show_steady();1-16 void key_scan 无返回值uchar key_scan 有返回值 return(i)错误提示：X1.C(28): error C174: return-expression on void-functionuchar Keys_Scan()/有返回值的函数，不可用voiduchar sCode,kCode,i,k;/低4位置0，放入4行P1=0xf0;/若高4位出现0，则有键按下if(P1&0xf0)!=0xf0)De

6、layMS(2);if(P1&0xf0)!=0xf0)sCode=0xfe;/行扫描码初值for(k=0;k4;k+)/对4行分别进行扫描P1=sCode;if(P1&0xf0)!=0xf0)kCode=P1;for(i=0;i16;i+)/查表得到按键序号并返回if(kCode=KeyCodeTablei)return(i);elsesCode=_crol_(sCode,1); return(-1);1-20 m=0x80;/共阳极，应该只有一个高电平扫描，m=0xfe是共阴极/*名称：数码管显示拨码开关编码说明：系统显示拨码开关所设置的编码000255*/ /74LS245 同相三态双向总

7、线收发器#include#include#define uchar unsigned char#define uint unsigned int/各数字的数码管段码（共阴）uchar code DSY_CODE=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f;/显示缓冲uchar DSY_Buffer3=0,0,0;/延时void DelayMS(uint ms)uchar t; while(ms-)for(t=0;t120;t+);/主程序void main()uchar i,m,Num;P0=0xff;P2=0xff;while(1)m=

8、0x80;/共阳极，应该只有一个高电平扫描，m=0xfe是共阴极Num=P1;/读取拨码开关的值DSY_Buffer0=Num/100;DSY_Buffer1=Num/10%10;DSY_Buffer2=Num%10;for(i=0;i3;i+)/刷新显示在所有数码管上m=_crol_(m,1);P2=m;P0=DSY_CODEDSY_Bufferi;DelayMS(10);1-24 P0口作为输出口使用时，由于输出电路是漏极开路电路，必须外接上拉电阻才能有高电平输出。1-25while(1); / /死循环，程序一直在执行，没有while(1),程序就结束了#include#define u

9、int unsigned int #define uchar unsigned charsbit LED1=P00;void init()LED1=1;EA=1;EX0=1;IT0=1; /跳沿触发，引脚INT0电平由高到低负跳变有效void enter0() interrupt 0 using 0LED1=LED1;void main()init();while(1); /死循环，程序一直在执行，没有while(1),程序就结束了1-26 中断优先级P1=0x00; /快速扫描时，留影，不然会产生丢失PX0=1;/外部中断0优先 外部中断0 void enter0() interrupt 0 using 0T0中断溢出void enter0() interrupt 1 using 0外部中断1void enter0() interrupt 2 using 0T1中断溢出void enter0() interrupt 3 using 0串行口中断void enter0() interrupt 4 using 0for(i=0;i6;i+)P1=0x00; /快速扫描时，留影，不然会产生丢失m=_cror_(m,1);P1=DSY_codeDSY_Bufferi;P2=m;delay(5);1-27 return