用打印机端口做可编程频率发生器电路

#includestdio.h

#includeconio.h

#includemath.h

#includebios.h

#includedos.h

#define CLK1 0x04 /* Clock Pulse High*/

#define CLK0 0xfb /* Clock Pulse Low*/

#define CS10x01 /* Chip Select high to deactivate DAC*/

#define CS0 0xfe /* Chip Select low to activate DAC*/

#define DATA1 0x02 /* Data Pulse High*/

#define DATA0 0xfd /* Data Pulse low*/

int c[16],dport,ACTUALDATA,out,k;/*Global Declarations*/

float VOUT;/*DAC OUTPUT-p.htm" target="_blank" title="OUTPUT货源和PDF资料">OUTPUT*/

void d2b(unsigned int x, int*c)/*Routine for Decimal to Binary Conversion*/

{

int i;

for(i=0;i=15;i )

*(c )=(xi) 0x1;

}

float ftov()/*Hertz to DAC output Conversion Routine*/

{

int HERTZ;

printf("\n \nEnter the frequencywithin 0 to 10000Hz:");

scanf("%d",HERTZ);

VOUT=0.00040955*HERTZ;

printf("\n VOUT=%f\n",VOUT);

return VOUT;

}

void CLOCK_DAC(void)/*Routine for clocking the DAC*/

{

out|=CLK1;

outportb(dport,out);/*Setting the clock high*/

delay(1);

out=CLK0;

outportb(dport,out);/*Setting the clock low*/

delay(1);

}

void LOAD_DACDATA(int*c)/*Routine for loading actual data into the DAC*/

{

out|=CS1;

outportb(dport,out);/*Chip Select high to disable DAC*/

delay(1);

out=CS0;

outportb(dport,out);/*Chip Select low to enable DAC*/

delay(1);

printf("\nDATA loaded into the DAC=");

for(k=15;k=0;k--)

{

out|=c[k];

outportb(dport,out);

printf("%d",c[k]);

delay(1);

CLOCK_DAC();

}

out|=CS1;

outportb(dport,out);

delay(1);

}

main()

{

int v,inc;

float y;

unsignedint x;

double fraction, integer, number;

clrscr();

printf("\tUse Your Printer Port as a Programmable Frequency Generator");

printf("\n\t\t\t by\n");

printf("\tK.Suresh,MSD,IGCAR,Kalpakkam,TamilNadu-603102,India");

dport= peek(0x40,8);/*Check up for availability of Printer Port*/

if (dport==0)

{

printf("\n\n LPT NOT AVIAILABLE! EXITING........");

exit(1);

}

printf("\n\nAddress of the printer port found =0x%X",dport);

ftov();

y=(VOUT*8192)/(2.5*1.6384);

v=y/1;

number=y;

fraction = modf(number, integer);

if (fraction0.44)

inc=0;

else inc=1;

ACTUALDATA=16384 v inc; /*Actual data including the Control Word for DAC*/

d2b(ACTUALDATA,c);

LOAD_DACDATA(c);

return 0;

}