a17.c

单片机实验程序-13种-17.4M-pdf.zip

// 	“验证式”	实验十七  D/A转换

#define LEDLen 6
#define MODE 0x03
xdata unsigned char CS0832 _at_ 0xa000;
xdata unsigned char CAddr  _at_ 0xe100;   // 命令控制口
xdata unsigned char OUTBIT _at_ 0xe101;   // 位控制口
xdata unsigned char CLK164 _at_ 0xe102;   // 段控制口(接164时钟位)
xdata unsigned char DAT164 _at_ 0xe102;   // 段控制口(接164数据位)
xdata unsigned char IN     _at_ 0xe103;   // 键盘读入口

unsigned char LEDBuf[LEDLen];  // 显示缓冲
code unsigned char LEDMAP[] = {  // 八段管显示码
  0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07,
  0x7f, 0x6f, 0x77, 0x7c, 0x39, 0x5e, 0x79, 0x71
};

void Delay(unsigned char CNT)
{
  unsigned char i;

  while (CNT-- !=0)
    for (i=100; i !=0; i--);
}

void DisplayLED()
{
  unsigned char i, j;
  unsigned char Pos;
  unsigned char LED;

  Pos = 0x20;  // 从左边开始显示
  for (i = 0; i < LEDLen; i++) {
    OUTBIT = 0;     // 关所有八段管
    LED = LEDBuf[i];
    for (j = 0; j < 8; j++) {   // 送164
     if (LED & 0x80) DAT164 = 1 ; else DAT164 = 0 ;
      CLK164 = CLK164| 0X02;
      CLK164 = CLK164& 0Xfd;
      LED <<= 1;
    }
    OUTBIT = Pos;  // 显示一位八段管
    Delay(1);
    Pos >>= 1;     // 显示下一位
  }
  OUTBIT = 0;     // 关所有八段管
}
void Write0832(unsigned char b)
{
  CS0832 = b;
}


void main()
{
   unsigned char i = 0;
   unsigned char j;
    unsigned char b;
   CAddr= MODE;
   while(1) {
     LEDBuf[0] = 0X3F;
     LEDBuf[1] = 0X7F;
     LEDBuf[2] = 0X4f;
     LEDBuf[3] = 0X5b;
     LEDBuf[4] = 0X00;
     LEDBuf[5] = 0X00;
     Write0832(i);
     LEDBuf[5] = LEDMAP[i & 0x0f] ;
     LEDBuf[4] = LEDMAP[i>>4 & 0x0f] ;
      i++;
     for(j=0; j<20; j++)
       DisplayLED();   // 延时
   }
    ;
}