dds.c

本系统的控制部分是以89C51为核心

//用于MCS51的C语言例子程序
//这是用于7279A评估板的C51子程序
#include<reg51.h>
//#include<at89x55>

//***函数定义***
void long_delay(void); //***长延时***
void short_delay(void); //***短延时***
void delay10ms(unsigned char); //延时10MS
void write7279(unsigned char, unsigned char);// 写入到HD7279
unsigned char read7279(unsigned char);// 从HD7279读出
void send_byte(unsigned char); //发送一个字节
unsigned char receive_byte(void); //接收一个字节

//**定义变量及I/O口**

unsigned char digit[5];
unsigned char key_number, j, k;
unsigned int tmr,sum=0;
unsigned char  cnter=1;

sbit cs=P1^0; // cs at P1.0
sbit clk=P1^1; // clk 连接于P1.1
sbit dat=P1^2; // data 连接于P1.2
sbit key=P1^3; // key 连接于P1.3

 //****** HD7279A指令 ******
#define CMD_RESET 0xa4  //复位（清除）指令
#define CMD_TEST 0xbf   //测试指令
#define DECODE0 0x80
#define DECODE1 0xc8
#define CMD_READ 0x15
#define UNDECODE 0x90
#define RTL_CYCLE 0xa3
#define RTR_CYCLE 0xa2
#define RTL_UNCYL 0xa1
#define RTR_UNCYL 0xa0
#define ACTCTL 0x98
#define SEGON 0xe0
#define SEGOFF 0xc0
#define BLINKCTL 0x88

//***主程序***
void main()
{
  while(1)
  {
 for (tmr=0;tmr<0x2000;tmr++); //上电延时
send_byte(CMD_RESET); // 复位HD7279A
  while (1)
    {
      if (!key) //如果有键按下
        {
         key_number=read7279(CMD_READ);//读出键码
         P0=key_number;
         //sum=sum+cnter*key_number;
         //cnter=cnter*10;
         write7279(DECODE1+7,key_number&0x0F);//显示键码
         send_byte(RTL_CYCLE); // 循环左移23次
         delay10ms(12);
         while (!key); //等待按键放开
         cnter+=1;
         }
      }
cnter=0;
  }
}

//**********************************************
//****写****
void write7279(unsigned char cmd, unsigned char dta)
{
send_byte (cmd);
send_byte (dta);
}

//*********读出********
unsigned char read7279(unsigned char command)
{
send_byte(command);
return(receive_byte());
}

//***发送***
void send_byte( unsigned char out_byte)
{
unsigned char i;
cs=0;
long_delay();
for (i=0;i<8;i++)
  {
  if (out_byte&0x80)
    {dat=1;}
  else
   {dat=0;}
  clk=1;
  short_delay();
  clk=0;
  short_delay();
  out_byte=out_byte*2;
  }
dat=0;
}

//***接收***
unsigned char receive_byte(void)
{
  unsigned char i, in_byte;
  dat=1;             //设为输入状态
  long_delay();
  for (i=0;i<8;i++)
  {
  clk=1;
  short_delay();
  in_byte=in_byte*2;
  if (dat)
    {in_byte=in_byte|0x01;}
  clk=0;
  short_delay();
  }
dat=0;
return (in_byte);
}

//***长延时***
void long_delay(void)
{
unsigned char i;
for (i=0;i<0x30;i++);
}

//***短延时***
void short_delay(void)
{
unsigned char i;
for (i=0;i<8;i++);
}
// ********************* 延时n*10ms **********************
void delay10ms(unsigned char time)
{
unsigned char i;
unsigned int j;
for (i=0;i<time;i++)
{
for(j=0;j<0x390;j++)
{
if (!key)
{
//key_int();
}
}
}
}