buff1024.c.txt

Parallel Port description of the communication port

 /* Name       : Sample Comm's Program - 1024 Byte Buffer - buff1024.c   */
 /* Written By : Craig Peacock <[e-mail]>                   */

 /*       Copyright 1997 CRAIG PEACOCK <[e-mail]>           */

 /*         See http://www.senet.com.au/~cpeacock/serial1.htm            */
 /*                       For More Information                           */

#include <dos.h>
#include <stdio.h>
#include <conio.h>

#define PORT1 0x3F8  /* Port Address Goes Here */
#define INTVECT 0x0C /* Com Port's IRQ here (Must also change PIC setting) */

  /* Defines Serial Ports Base Address */
  /* COM1 0x3F8                        */
  /* COM2 0x2F8			       */
  /* COM3 0x3E8			       */
  /* COM4 0x2E8			       */

int bufferin = 0;
int bufferout = 0;
char ch;
char buffer[1025];

void interrupt (*oldport1isr)();

void interrupt PORT1INT()  /* Interrupt Service Routine (ISR) for PORT1 */
{
 int c;
 do { c = inportb(PORT1 + 5);
      if (c & 1) {buffer[bufferin] = inportb(PORT1);
		  bufferin++;
		  if (bufferin == 1024) {bufferin = 0;}}
    }while (c & 1);
 outportb(0x20,0x20);
}

void main(void)
{
 int c;
 outportb(PORT1 + 1 , 0);        /* Turn off interrupts - Port1 */

 oldport1isr = getvect(INTVECT); /* Save old Interrupt Vector of later
				    recovery */

 setvect(INTVECT, PORT1INT);     /* Set Interrupt Vector Entry */
				 /* COM1 - 0x0C */
				 /* COM2 - 0x0B */
				 /* COM3 - 0x0C */
				 /* COM4 - 0x0B */

 /*         PORT 1 - Communication Settings         */

 outportb(PORT1 + 3 , 0x80);  /* SET DLAB ON */
 outportb(PORT1 + 0 , 0x0C);  /* Set Baud rate - Divisor Latch Low Byte */
			      /* Default 0x03 =  38,400 BPS */
			      /*         0x01 = 115,200 BPS */
			      /*         0x02 =  57,600 BPS */
			      /*         0x06 =  19,200 BPS */
			      /*         0x0C =   9,600 BPS */
			      /*         0x18 =   4,800 BPS */
			      /*         0x30 =   2,400 BPS */
 outportb(PORT1 + 1 , 0x00);  /* Set Baud rate - Divisor Latch High Byte */
 outportb(PORT1 + 3 , 0x03);  /* 8 Bits, No Parity, 1 Stop Bit */
 outportb(PORT1 + 2 , 0xC7);  /* FIFO Control Register */
 outportb(PORT1 + 4 , 0x0B);  /* Turn on DTR, RTS, and OUT2 */

 outportb(0x21,(inportb(0x21) & 0xEF));  /* Set Programmable Interrupt Controller */
					 /* COM1 (IRQ4) - 0xEF  */
					 /* COM2 (IRQ3) - 0xF7  */
					 /* COM3 (IRQ4) - 0xEF  */
					 /* COM4 (IRQ3) - 0xF7  */

 outportb(PORT1 + 1 , 0x01);  /* Interrupt when data received */

 printf("\nSample Comm's Program. Press ESC to quit \n");

 do {

     if (bufferin != bufferout){ch = buffer[bufferout];
				bufferout++;
				if (bufferout == 1024) {bufferout = 0;}
				printf("%c",ch);}

     if (kbhit()){c = getch();
		  outportb(PORT1, c);}

    } while (c !=27);

 outportb(PORT1 + 1 , 0);       /* Turn off interrupts - Port1 */
 outportb(0x21,(inportb(0x21) | 0x10));  /* MASK IRQ using PIC */
					 /* COM1 (IRQ4) - 0x10  */
					 /* COM2 (IRQ3) - 0x08  */
					 /* COM3 (IRQ4) - 0x10  */
					 /* COM4 (IRQ3) - 0x08  */
 setvect(INTVECT, oldport1isr); /* Restore old interrupt vector */

}