PCF8591A/D D/A之间转换

void write_address(uchar address,uchar date)

{

start();

write_byte(0x90);

respons();

write_byte(address);

respons();

write_byte(date);

respons();

stop();

}

uchar read_address(uchar address)

{

uchar date;

start();

write_byte(0x90); //10010000 前四位固定 接下来三位全部被接地了 所以都是0 最后一位是写 所以为低电平

respons();

write_byte(address);

respons();

start();

write_byte(0x91);

respons();

date=read_byte();

stop();

return date;

}

void display()

{

uchar i;

Ledout[0]=table[num0%10000/1000];

Ledout[1]=table[num0%1000/100];

Ledout[2]=table[num0%100/10];

Ledout[3]=table[num0%10];

Ledout[4]=table[num1%10000/1000];

Ledout[5]=table[num1%1000/100];

Ledout[6]=table[num1%100/10];

Ledout[7]=table[num1%10];

for(i=0;i<8;i++)

{

P0=Ledout[i];

switch(i)

{

case 0:LS138A=0; LS138B=0; LS138C=0; break;

case 1:LS138A=1; LS138B=0; LS138C=0; break;

case 2:LS138A=0; LS138B=1; LS138C=0; break;

case 3:LS138A=1; LS138B=1; LS138C=0; break;

case 4:LS138A=0; LS138B=0; LS138C=1; break;

case 5:LS138A=1; LS138B=0; LS138C=1; break;

case 6:LS138A=0; LS138B=1; LS138C=1; break;

case 7:LS138A=1; LS138B=1; LS138C=1; break;

}

delay1ms(2);

}

P0=0x00;

}

void main()

{

init();

AD_change=0;

while(1)

{

switch(AD_change)

{

case 0:num0=read_address(0x41);

break;

case 1:num1=read_address(0x42);

break;

case 2:num2=read_address(0x43);

break;

case 3:num3=read_address(0x40);

break;

case 4:write_address(0x40,num1);

break;

}

if(++AD_change>4)

{

AD_change=0;

}

display();

}

}