7279.c

7279是串行的LED键盘控制芯片

#include "MAIN.H"
//-------------------------------------------------------------------
extern ubyte KEY;
extern bit key_flag;
//-------------------------------------------------------------------
void delay(uword i);

//--------------------------------------------------------------------

void H_Delay(ubyte i){
for(;i>=2;){i--;}
return;
}

void HD7279_SendByte( unsigned char out_byte)
{ 
unsigned char i;
HD7279_CS=0; 
H_Delay(6); 
for(i=0;i<8;i++) 
{ 
if(out_byte&0x80) { HD7279_DATA=1; } 
else { HD7279_DATA=0; } 
HD7279_CLK=1; 
H_Delay(3); 
HD7279_CLK=0; 
H_Delay(3); 
out_byte=out_byte<<1;
} 
HD7279_DATA=0;
return;
}

void disp(ubyte cmd, ubyte dta) //写入7279
{
HD7279_SendByte(cmd);
H_Delay(2);
HD7279_SendByte(dta);
}


ubyte HD7279_ReceiveByte()
{ 
ubyte i, in_byte;
SFR_PAGE(_pp0, noSST);         // switch to page 0
P3_DIR        =  0xef;         // load direction register
HD7279_DATA=1; 
H_Delay(6); 
for(i=0;i<8;i++) 
{HD7279_CLK=1; 
H_Delay(3); 
in_byte=in_byte<<1; 
if(HD7279_DATA) { in_byte=in_byte|0x01; } 
HD7279_CLK=0; 
H_Delay(3); 
} 
HD7279_DATA=0; 
P3_DIR        =  0xff;         // load direction register
return (in_byte);
}
void Getkey(){
HD7279_SendByte(HD7279_READ);
KEY=HD7279_ReceiveByte();
key_flag=1;
return;
}