//
// Serial.c
//
//  Source based on code snippet from PICLIST.
//
#include "conio.h"
#include "viewer.h"

/* Serial Port Definitions */

#define   COM1_BASE   0x3F8       /* COM1 Base Address */
#define   COM2_BASE   0x2F8       /* COM2 Base Address */
#define   COM3_BASE   0x3E8       /* COM3 Base Address */
#define   COM4_BASE   0x2E8       /* COM4 Base Address */

    static int COM_BASE;
/*
   InitUSART() - Initialize USART to 9600, 8 Data Bits, No Parity, 1 Stop
   Bit
   */
void InitUSART( int Port )
{
      switch( Port ) {
	 case 1: COM_BASE = COM1_BASE; break;
	 case 2: COM_BASE = COM2_BASE; break;
	 case 3: COM_BASE = COM3_BASE; break;
	 case 4: COM_BASE = COM4_BASE; break;
	 default:
	 COM_BASE = COM1_BASE; break;
      }

      outp(COM_BASE + 1, 0x00);   /* Turn off interrupts                     */
      outp(COM_BASE + 3, 0x83);   /* Access Divisor Latch                    */
      outp(COM_BASE + 0, 0x0C);   /* Set 115200 Baud (115200/Divisor)        */
       /*                             Divisor = 115200/Baud rate
				    For 9600 Baud: Divisor = 12 (0x0C)
	*/
      outp(COM_BASE + 3, 0x03);   /* Access DFM reg. Configure Data Format   */
      outp(COM_BASE + 4, 0x00);   /* Disable Loop, !OUTx. Disable !RTS, !DTR */
      /*                 0x01 =      Disable Loop, !OUTx, !RTS. Enable !DTR
			 0x02 =      Disable Loop, !OUTx, !DTR. Enable !RTS
			 0x03 =      Disable Loop, !OUTx. Enable !RTS, !DTR
      */
}

/*
   TxData() - Send Data to Serial Port
   Entry:
	data = Data to transmit
*/
void TxData( int data )
{
     int x;

   /* Check for Tx Buffer Empty */
   do {
      x = inp(COM_BASE + 5);
      x &= 0x20;
   } while(x == 0);

   outp(COM_BASE + 0, data);       /* Send Data */
}

/*
   RxFlush() - Receive any data available from the Serial Port, ignore it
   Exit:
   data = Rx Data byte - last byte received
*/
int RxFlush( void )
{            int x,data;
  do {
     x = inp(COM_BASE + 5);
     x &= 0x01;
     if (x == 1)
     {
       data = inp(COM_BASE + 0);   /* Get Data          */
     }
   } while ( x == 1 );
   return( data );
}

/*
   RxData() - Receive Data from the Serial Port
   Exit:
   data = Rx Data byte
*/
int RxData(void)
{
      int x;
      int data = 0;

  while( 1 )                     /* Check for Rx Data */
  {
     x = inp(COM_BASE + 5);
     x &= 0x01;
     if(x == 1)
     {
       data = inp(COM_BASE + 0);   /* Get Data          */
       break;
     }
     if(kbhit())                   /* Abort if Keypress */
     {
	data = -1;
	break;
     }
  }
  return(data);
}