哈哈，还是老Ｘ的那工具**，再出一个思考题

//古道热肠U盘开发板--AD驱动//主办单位:www.21ic.com//项目负责人：古道热肠//作者邮箱：xg_2004_sy@126.com//Blog    : http://blog.21ic.com/user1/4538/index.html//完成日期：2008-12-02//备注：  开发板上AD4-AD7为有效AD入口#include <AT91SAM7S64.H>                    /* AT91SAM7S64 definitions */#include <lib_AT91SAM7s64.h>#include <string.h>#include <stdio.h>#include "..Board.h"#include "DriverLCD_Nokia5110.h"#include "DriverBeep.h"#include "DriverTwi.h"#include "DriverTimer.h"#include "Serial.h"#include "APIComm.h"//初始化硬件为AD模块服务void  ADC_Init(){            AT91F_ADC_SoftReset(AT91C_BASE_ADC);      //Hradware triggers are disabled. Starting a conversion is only possible by software      //8-bit ,set adc clock,the startup time,sample and holding time.      AT91F_ADC_CfgModeReg(AT91C_BASE_ADC,AT91C_ADC_TRGEN_DIS | AT91C_ADC_LOWRES_10_BIT | AT91C_ADC_SLEEP_NORMAL_MODE                              | AT91C_ADC_PRESCAL | AT91C_ADC_STARTUP | AT91C_ADC_SHTIM);      AT91F_ADC_EnableChannel(AT91C_BASE_ADC,AT91C_ADC_CH4 | AT91C_ADC_CH5 | AT91C_ADC_CH6 | AT91C_ADC_CH7);//      AT91F_ADC_StartConversion(AT91C_BASE_ADC);         `}//等待AD转换结束//返回:true 表示读取到转换结束标志符,属转换正常结束//     false 表示超时退出，功能出错//备注:根据文档介绍:转换时间最大值为2usbool ADC_WaitEnd(void){      uint uiReadValue;      uint uiDelayCount;            //10uS计数值的倍数      bool bReturnValue;      bReturnValue = false;      uiDelayCount = 0;      Timer_Start();            //开启定时器      while(uiDelayCount<2)      {            uiDelayCount = GetTimerCount();            uiReadValue = AT91F_ADC_GetStatus(AT91C_BASE_ADC);            if((uiReadValue & 0x000000f0) == 0x000000f0)   //仅启用了CH4-CH7通道            {                  bReturnValue = true;                  break;            }      }      return(bReturnValue);}void ADC_Start(void){       AT91F_ADC_StartConversion(AT91C_BASE_ADC);}//读取AD转换通道的值，入口参数，AD通道号索引，返回与通道号对应的AD值uint ADC_ReadValue(uchar ucChannelIndex){      uint uiReadValue;      switch(ucChannelIndex)      {            case AT91C_ADC_CH4:                  uiReadValue =  AT91F_ADC_GetConvertedDataCH4(AT91C_BASE_ADC);                  break;            case AT91C_ADC_CH5:                  uiReadValue =  AT91F_ADC_GetConvertedDataCH5(AT91C_BASE_ADC);                  break;            case AT91C_ADC_CH6:                  uiReadValue =  AT91F_ADC_GetConvertedDataCH6(AT91C_BASE_ADC);                  break;            case AT91C_ADC_CH7:                  uiReadValue =  AT91F_ADC_GetConvertedDataCH7(AT91C_BASE_ADC);                  break;            default:                  uiReadValue = 0;                  break;      }      return(uiReadValue);}void TestAD(void){      uint uiReadADValue;      uchar ucDispDataBuff[16];      LCD_Clear();      LCD_ShowString(0,0,"  Test AD");      ADC_Init();      while(1)      {            ComShowString(c_COM1,"Start AD Convert");            ADC_Start();            ADC_WaitEnd();             ComShowString(c_COM1,"AD Convert Complete");            uiReadADValue =  ADC_ReadValue(AT91C_ADC_CH4);            sprintf(ucDispDataBuff,"CH4 AD Value is:%4d",uiReadADValue);            ComShowString(c_COM1,ucDispDataBuff);            LCD_ShowString(0,1,ucDispDataBuff);            uiReadADValue =  ADC_ReadValue(AT91C_ADC_CH5);            sprintf(ucDispDataBuff,"CH5 AD Value is:%4d",uiReadADValue);            ComShowString(c_COM1,ucDispDataBuff);//            LCD_ShowString(0,1,ucDispDataBuff);            uiReadADValue =  ADC_ReadValue(AT91C_ADC_CH6);            sprintf(ucDispDataBuff,"CH6 AD Value is:%4d",uiReadADValue);            ComShowString(c_COM1,ucDispDataBuff);//            LCD_ShowString(0,1,ucDispDataBuff);            uiReadADValue =  ADC_ReadValue(AT91C_ADC_CH7);            sprintf(ucDispDataBuff,"CH7 AD Value is:%4d",uiReadADValue);            ComShowString(c_COM1,ucDispDataBuff);            LCD_ShowString(0,3,ucDispDataBuff);                        Delay(1);      }}enum KeyV {                  KEY_LEFT,                   KEY_DOWN,                    KEY_RIGHT,                  KEY_NONE,                   KEY_ESC,                   KEY_UP,                   KEY_OK                  };const enum KeyV Ktab[] = {KEY_LEFT, KEY_DOWN,  KEY_RIGHT, KEY_NONE, KEY_ESC, KEY_UP,KEY_OK};enum KeyV  Read_KeyValue(void)                          {      uchar uci;      uint uiReadADCValue;      enum KeyV enuKeyReturnValue;      const unsigned short KeyTable[] ={ 0, 100, 260, 390, 470, 560, 690, 1023};//      ADC_Start();      //由于上一次读取结束时启动了AD转换,所以直接等转换结束后读AD值即可      if(ADC_WaitEnd())      {             uiReadADCValue = ADC_ReadValue(AT91C_ADC_CH4);            for(uci=0;uci<7;uci++)             {                  if(( KeyTable[uci] <= uiReadADCValue) &&                      (uiReadADCValue < KeyTable[uci+1] ) )                  {                        enuKeyReturnValue = Ktab[uci];                        break;                  }            }      }      else      {            enuKeyReturnValue = KEY_NONE;            }      //读取完当前的AD值后,再次启动转换过程      ADC_Start();      return enuKeyReturnValue;}enum KeyV ReadKey(void) {      static int KeyCount=0;                              static enum KeyV preKey=KEY_NONE;      //存放前一次按键的值      enum KeyV CurrentKeyValue;            CurrentKeyValue = Read_KeyValue();      if(CurrentKeyValue == preKey)       {            KeyCount++;        //防抖动处理            if(KeyCount > 10)             //重复检查次数为10次，完全相符，认为按键有效            {                  KeyCount=0;                  return CurrentKeyValue;                  }      }      else       {            KeyCount=0;      }      preKey = CurrentKeyValue;      return KEY_NONE;}bool KbHit(void){      enum KeyV ucReadKeyValue;      ucReadKeyValue = Read_KeyValue();      if(ucReadKeyValue != KEY_NONE)      {            return(true);      }      else      {            return(false);      }}//读取按键值，无阻塞，读完后没有等待按键释放就返回主调函数enum KeyV KbGet(void){      enum KeyV ucKeyValue;      uchar ucCount;      ucCount= 30;      while(ucCount--)      {            ucKeyValue = ReadKey();            if(ucKeyValue != KEY_NONE)            {                  break;            }            Delay(1);      }      return ucKeyValue;}void TestAD_KeyBoard(void){      uchar uci;      enum KeyV ucKeyValue;//       init_timer();      LCD_Clear();      LCD_ShowString(0,0,"Test AD KBD");      ADC_Init();               //初始化AD是必须执行的操作      //启动一次转换过程，初始化AD模块的读取、启动的循环。      ADC_Start();      Delay(1);      while(1)      {            if(KbHit())            {                  ComShowString(c_COM1,"Find Key Press");                   ucKeyValue = KbGet();                   switch(ucKeyValue)                   {                         case KEY_ESC:                              LCD_ShowString(0,2,"Esc Press");                              break;                         case KEY_UP:                              LCD_ShowString(0,2,"UP Press");                              break;                         case KEY_OK:                              LCD_ShowString(0,2,"OK Press");                              break;                         case KEY_LEFT:                              LCD_ShowString(0,2,"LEFT Press");                              break;                         case KEY_DOWN:                              LCD_ShowString(0,2,"Down Press");                              break;                          case KEY_RIGHT:                              LCD_ShowString(0,2,"Right Press");                              break;                        default:                              LCD_ShowString(0,2,"Err!");                                 break;                   }                   //等待按键释放。                   while(KbHit())                   {      //                   BeepShort();                        Delay(1);                   }            }            Delay(1);      }}