主要器件：

1、  AT89C52单片机芯片，用于控制信号发生芯片，实现不同波形的选择和输出。

2、  高频波形发生器MAX038，具有高频率、高精度、低输出电阻、驱动能力强等特点。

3、  简单的按键选择电路。

试验流程图：
 

试验程序代码：

//SignalGen.h程序

#ifndef    _SIGNALGEN_H                // 防止SignalGen.h被重复引用

#define    _SIGNALGEN_H

#include                    // 引用标准库的头文件

#define uchar unsigned char

uchar key;                                         // 按键值

sbit A0 = P2^0;                                  // MAX038的波形选择位A0

sbit A1 = P2^1;                                  // MAX038的波形选择位A1

void delay();

uchar keyscan();

#endif

//SignalGen.c程序

#include "SignalGen.h"

/* 用于键消抖的延时函数 */

void delay()

{

       uchar i;

       for (i=400;i>0;i--);

}

/* 键扫描函数 */

uchar keyscan(void)

{

       uchar scancode,tmpcode;

       P1 = 0xf0;                                                     // 发全0行扫描码

       if ((P1&0xf0)!=0xf0)                                // 若有键按下

       {

              delay();                                             // 延时去抖动

              if ((P1&0xf0)!=0xf0)                         // 延时后再判断一次，去除抖动影响

              {

                     scancode = 0xfe;

                     while((scancode&0x10)!=0)         // 逐行扫描

                     {

                            P1 = scancode;                           // 输出行扫描码

                            if ((P1&0xf0)!=0xf0)           // 本行有键按下

                            {

                                   tmpcode = (P1&0xf0)|0x0f;

                                   /* 返回特征字节码，为1的位即对应于行和列 */

                                   return((~scancode)+(~tmpcode));

                            }

                            else scancode = (scancode<<1)|0x01;         // 行扫描码左移一位

                     }

              }

       }

       return(0);                                                        // 无键按下，返回值为0   

}

/* 主程序 */

void main()

{

       uchar key;

      while(1)

    {

              key = keyscan();                  // 调用键盘扫描函数

              delay();

              switch(key)

            {

                 case 0x11:                           // 第1行第1列，选择正弦波输出

                            A0 = 0;                       

                            A1 = 1;

                            break;

                     case 0x21:                           // 第1行第2列，选择矩形波输出

                            A0 = 0;                       

                            A1 = 0;

                            break;                  

                     case 0x41:                           // 第1行第3列，选择三角波输出

                            A0 = 1;                       

                            A1 = 0;

                            break;               

                     default:break;

               }

       }

}