B&B Electronics Parallel Printer Card PIOC Manuale Utente Scaricare il pdf (Pagina 13)

Interfacing the Standard Parallel Port http://www.senet.com.au/~cpeacock

Interfacing the Standard Parallel Port Page 13

void interrupt (*oldhandler)();

void interrupt parisr() /* Interrupt Service Routine (ISR) */

{

interflag = 1;

outportb(picaddr,0x20); /* End of Interrupt (EOI) */

}

void main(void)

{

int c;

int intno; /* Interrupt Vector Number */

int picmask; /* PIC's Mask */

/* Calculate Interrupt Vector, PIC Addr & Mask. */

if (IRQ >= 2 && IRQ <= 7) {

intno = IRQ + 0x08;

picaddr = PIC1;

picmask = 1;

picmask = picmask << IRQ;

}

if (IRQ >= 8 && IRQ <= 15) {

intno = IRQ + 0x68;

picaddr = PIC2;

picmask = 1;

picmask = picmask << (IRQ-8);

}

if (IRQ < 2 || IRQ > 15)

{

printf("IRQ Out of Range\n");

exit();

}

outportb(CONTROL, inportb(CONTROL) & 0xDF); /* Make sure port is in Forward Direction */

outportb(DATA,0xFF);

oldhandler = getvect(intno); /* Save Old Interrupt Vector */

setvect(intno, parisr); /* Set New Interrupt Vector Entry */

outportb(picaddr+1,inportb(picaddr+1) & (0xFF - picmask)); /* Un-Mask Pic */

outportb(CONTROL, inportb(CONTROL) | 0x10); /* Enable Parallel Port IRQ's */

clrscr();

printf("Parallel Port Interrupt Polarity Tester\n");

printf("IRQ %d : INTNO %02X : PIC Addr 0x%X : Mask 0x%02X\n",IRQ,intno,picaddr,picmask);

interflag = 0; /* Reset Interrupt Flag */

delay(10);

outportb(DATA,0x00); /* High to Low Transition */

delay(10); /* Wait */

if (interflag == 1) printf("Interrupts Occur on High to Low Transition of ACK.\n");

else

{

outportb(DATA,0xFF); /* Low to High Transition */

delay(10); /* wait */

if (interflag == 1) printf("Interrupts Occur on Low to High Transition of ACK.\n");

else printf("No Interrupt Activity Occurred. \nCheck IRQ Number, Port Address ”

“and Wiring.");

}

outportb(CONTROL, inportb(CONTROL) & 0xEF); /* Disable Parallel Port IRQ's */

outportb(picaddr+1,inportb(picaddr+1) | picmask); /* Mask Pic */

setvect(intno, oldhandler); /* Restore old Interrupt Vector Before Exit */

}

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B&B Electronics Parallel Printer Card PIOC Manuale Utente Pagina 13

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