設計一個信號發生器,能在單片機的基礎上控制并產生正弦波、方波、三角波和鋸齒波,且頻率幅度和波形以及占空比可以通過按鍵改變。
制作出來的實物圖:
Altium Designer畫的信號發生器原理圖和PCB圖如下:(51hei附件中可下載工程文件)
單片機信號發生器仿真原理圖如下(proteus仿真工程文件可到本帖附件中下載)
單片機波形發生器ppt內容預覽:
利用單片機編寫程序,然后將產生信號通過DAC0832
(數模轉換器)轉化成模擬信號,輸入信號經運放電路后信號放大,低通濾波是輸出的信號穩定不失真。最后在液晶屏LCD1602上實時顯示。此外,5個按鍵可對增益進行直接設定。
電流/電壓轉換放大電路
由于從DAC0832轉換出來的模擬信號為電流信號,為了方便觀測輸出信號的特征,將DAC0832輸出的信號經過電流/電壓轉換放大電路轉變為電壓信號。本設計中使用的運放為LM324。LM324運算放大器是價格便宜的帶差動輸入功能的四運算放大器
DAC0832和兩片 LM324實現雙極性輸出
5個獨立鍵盤和一個2輸入與門組成,其中與門輸出端連接單片機的P3.2口以便形成外部中斷。5個按鍵分別連接單片機的P2.0~P2.4口。2輸入與門一引腳與K1按鍵相連,另一引腳接高電平。當K1按下時,INT0為低電平,可知外部中斷到了,系統執行中斷程序。當K2~K5按鍵某一個按下時,對應的P2.1~P2.4口中某個為低電平,系統可以感知此按鍵按下,從而執行相應的程序。
使自變量i不斷的自動加1,若i的值小于squa_num,將P0口賦值為0xFF;若i的值大于squa_num,則將P0口賦值為0x00。當i自加到256后又自動變為0,以此循環,即可得到矩形波。當squa_num=128時,此時輸出的為方波。調節squa_num的大小,即可實現矩形波占空比的調節;調節延時時間的大小,即可實現矩形波頻率的改變。
當波形選擇按鍵K1按下時,進入中斷程序中,此時波形選擇標識WaveChoice加1,LCD液晶顯示屏上顯示出相應的波形類型。中斷結束后,主程序中根據WaveChoice的值輸出相應的波形
總結:
因為我對單片機的認識還不夠深刻,課本知識也不夠應用,在硬件的使用與搭建上出了問題,導致我最后的實物無法正常顯示實驗的所需數據,剛剛開始我是盲目認為在做個板子就可以解決問題,后來在老師建議下,我明白應該要一步步找出錯誤,針對出現的問題來進行針對性的解決,而不是重復的做實物。最終我發現LCD之所以不亮說是因為我在布線的時候短路了,調整以后LCD可以正常顯示,但是無法將產生的信號顯示出來,有待改進!
單片機源程序如下:
- #include <reg51.h>
- #include<string.h>
- #define uchar unsigned char
- #define uint unsigned int
- sbit RS=P3^0;
- sbit RW=P3^1;
- sbit EN=P3^3;
- sbit K1=P2^0;
- sbit K2=P2^1;
- sbit K3=P2^2;
- sbit K4=P2^3;
- sbit K5=P2^4;
- uchar WaveChoice=1;
- uchar ys=30;
- uchar i,a=0;
- uchar sqar_num=128;
- uint freq;
- uchar code Sin[]={"Sine "};
- uchar code Squ[]={"Square "} ;
- uchar code Tri[]={"Triangle "};
- uchar code Saw[]={"Sawtooth "} ;
- uchar code No[]={"No Signal out "};
- uchar code Wave[]={"Wave :"};
- uchar code Fre[]={"Freq :"};
- uchar code tosin[256]=
- {0x80,0x83,0x86,0x89,0x8d,0x90,0x93,0x96,0x99,0x9c,0x9f,0xa2,0xa5,0xa8,0xab,
- 0xae,0xb1,0xb4,0xb7,0xba,0xbc,0xbf,0xc2,0xc5,0xc7,0xca,0xcc,0xcf,0xd1,0xd4,0xd6,0xd8,
- 0xda,0xdd,0xdf,0xe1,0xe3,0xe5,0xe7,0xe9,0xea,0xec,0xee,0xef,0xf1,0xf2,0xf4,
- 0xf5,0xf6,0xf7,0xf8,0xf9,0xfa,0xfb,0xfc,0xfd,0xfd,0xfe,0xff,0xff,0xff,0xff,0xff,0xff,
- 0xff,0xff,0xff,0xff,0xff,0xff,0xfe,0xfd,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf7,0xf6,0xf5,
- 0xf4,0xf2,0xf1,0xef,0xee,0xec,0xea,0xe9,0xe7,0xe5,0xe3,0xe1,0xde,0xdd,0xda,0xd8,
- 0xd6,0xd4,0xd1,0xcf,0xcc,0xca,0xc7,0xc5,0xc2,0xbf,0xbc,0xba,0xb7,0xb4,0xb1,0xae,0xab,
- 0xa8,0xa5,0xa2,0x9f,0x9c,0x99,0x96,0x93,0x90,0x8d,0x89,0x86,0x83,0x80,
- 0x80,0x7c,0x79,0x76,0x72,0x6f,0x6c,0x69,0x66,0x63,0x60,0x5d,0x5a,0x57,0x55,
- 0x51,0x4e,0x4c,0x48,0x45,0x43,0x40,0x3d,0x3a,0x38,0x35,0x33,0x30,0x2e,0x2b,
- 0x29,0x27,0x25,0x22,0x20,0x1e,0x1c,0x1a,0x18,0x16,0x15,0x13,0x11,0x10,0x0e,
- 0x0d,0x0b,0x0a,0x09,0x08,0x07,0x06,0x05,0x04,0x03,0x02,0x02,0x01,0x00,0x00,
- 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x02 ,0x02,0x03,0x04,
- 0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0d,0x0e,0x10,0x11,0x13,0x15,0x16,0x18,
- 0x1a,0x1c,0x1e,0x20,0x22,0x25,0x27,0x29,0x2b,0x2e,0x30,0x33,0x35,0x38,0x3a,
- 0x3d,0x40,0x43,0x45,0x48,0x4c,0x4e ,0x51,0x55,0x57,0x5a,0x5d,0x60,0x63,0x66 ,
- 0x69,0x6c,0x6f,0x72,0x76,0x79,0x7c,0x80 };
- void DelayMS(uchar ms)
- {
- uchar i;
- while(ms--) for(i=0;i<120;i++);
- }
- void Delay1(uint y)
- {
- uint i;
- for(i=y;i>0;i--);
- }
- uchar Busy_Check()
- {
- uchar LCD_Status;
- RS=0; // 寄存器選擇
- RW=1; //讀狀態寄存器
- EN=1; // 開始讀
- DelayMS(1);
- LCD_Status=P1;
- EN=0;
- return LCD_Status;
- }
- void Write_LCD_Command(uchar cmd)
- {
- while((Busy_Check()&0x80)==0x80); //忙等待
- RS=0; //選擇命令寄存器
- RW=0; //寫
- EN=0;
- P1=cmd;EN=1;DelayMS(1);EN=0;
- }
- void Write_LCD_Data(uchar dat)
- {
- while((Busy_Check()&0x80)==0x80); //忙等待
- RS=1; RW=0; EN=0; P1=dat;EN=1;DelayMS(1);EN=0;
- }
- void Init_LCD()
- {
- Write_LCD_Command(0x38);
- DelayMS(1);
- Write_LCD_Command(0x01); //清屏
- DelayMS(1);
- Write_LCD_Command(0x06); //字符進入模式:屏幕不動,字符后移
- DelayMS(1);
- Write_LCD_Command(0x0C); //顯示開、關光標
- DelayMS(1);
- }
- void Write_freq(uint k)
- {
- uchar qian,bai,shi,ge;
- qian=k/1000;
- bai=k/100%10;
- shi=k/10%10;
- ge=k%10;
- Write_LCD_Command(0x86+0x40);
- Write_LCD_Data(0x30+qian);
- Write_LCD_Data(0x30+bai);
- Write_LCD_Data(0x30+shi);
- Write_LCD_Data(0x30+ge);
- Write_LCD_Data(0x48);
- Write_LCD_Data(0x5a);
- }
- void Xianshi_f()
- {
- if(WaveChoice==1)
- {
- freq=(10000000/(50000+2860*ys));
- Write_freq(freq);
- }
- if(WaveChoice==2)
- {
- freq=(10000000/(50000+2300*ys));
- Write_freq(freq);
- }
- if(WaveChoice==3)
- {
- freq=(10000000/(14000+2300*ys));
- Write_freq(freq);
- }
- if(WaveChoice==4)
- {
- freq=(10000000/(15000+2300*ys));
- Write_freq(freq);
- }
- }
- void Write_wave(uchar t )
- {
- switch(t)
- {
- case 0:
- Write_LCD_Command(0x86);
- DelayMS(5);
- for (i=0;i<sizeof(No)-1;i++)
- {
- Write_LCD_Data(No[i]);
- DelayMS(5);
- }
- break;
- case 1:
- ys=25;
- Write_LCD_Command(0x86);
- DelayMS(5);
- for (i=0;i<sizeof(Sin)-1;i++)
- {
- Write_LCD_Data(Sin[i]);
- DelayMS(5);
- }
- break;
- case 2:
- ys=30;
- Write_LCD_Command(0x86);
- DelayMS(5);
- for (i=0;i<sizeof(Squ)-1;i++)
- {
- Write_LCD_Data(Squ[i]);
- DelayMS(5);
- }
-
- break;
- case 3:
- ys=30;
- Write_LCD_Command(0x86);
- DelayMS(5);
- for (i=0;i<sizeof(Tri)-1;i++)
- {
- Write_LCD_Data(Tri[i]);
- DelayMS(5);
- }
- break;
- case 4:
- ys=30;
- Write_LCD_Command(0x86);//液晶顯示位置
- DelayMS(5);
- for (i=0;i<sizeof(Saw)-1;i++)
- {
- Write_LCD_Data(Saw[i]);
- DelayMS(5);
- }
- break;
- }
- }
- void Out_Wave(uchar i)
- { uchar j;
- switch(i)
- {
- case 0: P0=0x00;break;
- case 1:
- for (j=0;j<255;j++)
- {
- P0=tosin[j];
- Delay1(ys);
- }
- break;
- case 2:
- {
- if(a<sqar_num)
- {
- P0=0xff;
- Delay1(ys);
- }
- else
- {
- P0=0x00;
- Delay1(ys);
- }
- a++;
- } break;
- case 3:
- {
- if(a<128)
- {
- P0=a;
- Delay1(ys);
- }
- else
- {
- P0=255-a;
- Delay1(ys);
- }
- a++;
- } break;
- case 4:
- {
- if(a<255)
- {
- P0=a;
- Delay1(ys);
- }
-
- a++;
- if(a==255)
- {
- a=0;
- } break;
- }
- }
- }
- void keyscanf()
- {
- if(K2==0)
- {
- DelayMS(5);
- if(K2==0)
- {
- while(!K2);
- ys--;
- if(ys==0)
- ys=20;
- }
- }
- if(K3==0)
- {
- DelayMS(5);
- if(K3==0)
- {
- while(!K3);
- ys++;
- if(ys>22)
- ys=20;
- }
- }
- if(K4==0)
- {
- DelayMS(5);
- if(K4==0)
- {
- while(!K4);
- if(WaveChoice==2)
- sqar_num=sqar_num+2;
- if(sqar_num==238)
- sqar_num=128;
- }
- }
- if(K5==0)
- {
- DelayMS(5);
- if(K5==0)
- {
- while(!K5);
- if(WaveChoice==2)
- sqar_num=sqar_num-2;
- if(sqar_num==18)
- sqar_num=128;
- }
- }
- }
- ……………………
- …………限于本文篇幅 余下代碼請從51黑下載附件…………
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波形發生器.7z
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2018-12-16 23:12 上傳
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