问答

11-2.C(40): error C231: 'keyscan_num': redefinition 11-2.C(41): error C141: syntax error near 'return' 11-2.C(41): error C231: 'keyscan_num': redefinition 11-2.C(42): error C141: syntax error near '}' 程序如下： #include sbit wr=P3^6; sbit rd=P3^2; sbit key0=P1^0; //定义P1.0脚的按键为正弦波键key0 sbit key1=P1^1; //定义P1.1脚的按键为方波键key1 sbit key2=P1^2; //定义P1.2脚的按键为三角波键key2 sbit key3=P1^3; //定义P1.3脚的按键为梯形波键key3 sbit key4=P1^4; //定义P1.3脚的按键为锯齿波键key4 unsigned char flag; unsigned char const code //以下为正弦波采样点数组256个数据 SIN_code[256]={0x80,0x83,0x86,0x89,0x8c,0x8f,0x92,0x95,0x98,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,0xae,0xb0,0xb3,0xb6,0xb9,0xbc,0xbf,0xc1,0xc4,0xc7,0xc9,0xcc,0xce,0xd1,0xd3,0xd5,0xd8,0xda,0xdc,0xde,0xe0,0xe2,0xe4,0xe6,0xe8,0xea,0xec,0xed,0xef,0xf0,0xf2,0xf3,0xf4,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfc,0xfd,0xfe,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfe,0xfd,0xfc,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,0xf3,0xf2,0xf0,0xef,0xed,0xec,0xea,0xe8,0xe6,0xe4,0xe3,0xe1,0xde,0xdc,0xda,0xd8,0xd6,0xd3,0xd1,0xce,0xcc,0xc9,0xc7,0xc4,0xc1,0xbf,0xbc,0xb9,0xb6,0xb4,0xb1,0xae,0xab,0xa8,0xa5,0xa2,0x9f,0x9c,0x99,0x96,0x92,0x8f,0x8c,0x89,0x86,0x83,0x80,0x7d,0x79,0x76,0x73,0x70,0x6d,0x6a,0x67,0x64,0x61,0x5e,0x5b,0x58,0x55,0x52,0x4f,0x4c,0x49,0x46,0x43,0x41,0x3e,0x3b,0x39,0x36,0x33,0x31,0x2e,0x2c,0x2a,0x27,0x25,0x23,0x21,0x1f,0x1d,0x1b,0x19,0x17,0x15,0x14,0x12,0x10,0xf,0xd,0xc,0xb,0x9,0x8,0x7,0x6,0x5,0x4,0x3,0x3,0x2,0x1,0x1,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x0,0x1,0x1,0x2,0x3,0x3,0x4,0x5,0x6,0x7,0x8,0x9,0xa,0xc,0xd,0xe,0x10,0x12,0x13,0x15,0x17,0x18,0x1a,0x1c,0x1e,0x20,0x23,0x25,0x27,0x29,0x2c,0x2e,0x30,0x33,0x35,0x38,0x3b,0x3d,0x40,0x43,0x46,0x48,0x4b,0x4e,0x51,0x54,0x57,0x5a,0x5d,0x60,0x63,0x66,0x69,0x6c,0x6f,0x73,0x76,0x79,0x7c} unsigned char keyscan() //键盘扫描函数 { unsigned char keyscan_num,temp; P1=0xff; // P1口输入 temp=P1; //从P1口读入键值，存入temp中 if(~(temp&0xff)) //判是否有键按下，即键值不为0xff，则有键按下 { if(key0==0) //产生正弦波的按键按下， { keyscan_num=1; //得到的键值为1，表示产生正弦波 } else if(key1==0) //产生方波的按键按下， { keyscan_num=2; //得到键值为2，表示产生方波 } else if(key2==0) //产生三角波的按键按下， P1.2=0 { keyscan_num=3; //得到的键值为3，表示产生三角波 } else if(key3==0) //产生梯形波的按键按下，P1.3=0 { keyscan_num=4; //得到的键值为4，表示产生梯形波 } else if(key4==0) { keyscan_num=5; } else keyscan_num=0; return(keyscan_num); } } void init_DA0832() { rd=0; wr=0; } void SIN() { unsigned int i; do{ P2=SIN_code[i]; i=i+1; }while(i<256); } void Square() { EA=1; ET0=1; TMOD=1; TH0=0xff; TL0=0x83; TR0=1; } void Triangle() { P2=0x00; do{ P2=P2+1; }while(P2<0xff); P2=0xff; do{ P2=P2-1; }while(P2>0x00); P2=0x00; } void Sawtooth() { P2=0x00; do{ P2=P2+1; }while(P2<0xff); } void Trapezoidal() { unsigned char i; P2=0x00; do{ P2=P2+1; }while(P2<0xff); P2=0xff; for(i=255;i>0;i--) { P2=0xff; } do{ P2=P2-1; }while(P2>0x00); P2=0x00; } void main() // 主函数 { init_DA0832(); // DA0832的初始化函数 do { flag=keyscan(); //将键盘扫描函数得到的键值赋给flag }while(!flag); while(1) { switch(flag) { case 1: do{ flag=keyscan(); SIN( ); }while(flag==1); break; case 2: Square (); do{ flag=keyscan(); }while(flag==2); TR0=0; break; case 3: do{ flag=keyscan(); Triangle (); }while(flag==3); break; case 4: do{ flag=keyscan(); Trapezoidal (); }while(flag==4); break; case 5: do{ flag=keyscan(); Sawtooth (); }while(flag==5); break; default: flag=keyscan(); break; } } } void timer0(void) interrupt 1 //定时器T0的中断函数 { P2=~P2; //方波的输出电平求反 TH0=0xff; //重装定时时间常数 TL0=0x83; TR0=1; //启动定时器T0 }