Category : Files from Magazines
Archive   : CUJ9209.ZIP
Filename : 1009044A

/*** LISTING 2 ***/
/*** ***/
/*** set.c ***/
/*** **************************************** ***/
/*** SET SERIAL PARAMETERS ***/
/*** **************************************** ***/
#include "serial.h"

int portbase;

int SetSerial (int ComPort,long Baud,int Parity,
int DataBits,int StopBits)
{
if (SetPort(ComPort))
{
return (-1);
}

if (SetBaud(Baud))
{
return (-1);
}

if (SetOthers(Parity,DataBits,StopBits))
{
return (-1);
}

return (0);
}

/*** **************************************** ***/
/*** SET THE PORT VALUE TO CORRECT COM PORT ***/
/*** **************************************** ***/

int SetPort (int ComPort)
{
switch (ComPort)
{
case COM1: portbase = COM1BASE;
break;

case COM2: portbase = COM2BASE;
break;

case COM3: portbase = COM3BASE;
break;

case COM4: portbase = COM4BASE;
break;

default: return (-1);
}
return (0);
}

/*** **************************************** ***/
/*** SET THE BAUD RATE - DLAB MUST BE SET ON.***/
/*** **************************************** ***/
int SetBaud (long Baud)
{
char Current_Value;
int divisor;

if ((Baud <= 0) || (Baud > 115200L))
{
return (-1);
}

else
{
divisor = (int)(115200L/Baud);
}

/*** READ CURRENT VALUES IN LINE CONTROL REG ***/

Current_Value = inp(portbase + LCR);

/*** OR CURRENT VALUE WITH 0x80 TO SET DLAB ***/

outp(portbase + LCR,(Current_Value | DLAB));

/*** OUTPUT BAUD DIVISOR TO LOW BYTE ***/

outp(portbase + DLL,(divisor & 0x00FF));

/*** OUTPUT BAUD DIVISOR TO HIGH BYTE ***/

outp(portbase + DLH,((divisor >> 8) & 0x00FF));

/*** TURN DLAB OFF BY SENDING CURRENT VALUE ***/

outp(portbase + LCR,Current_Value);

return (0);
}

/*** **************************************** ***/
/*** SET PARITY, DATA BITS, AND STOPBITS ***/
/*** **************************************** ***/
int SetOthers (int Parity,int DataBits,int StopBits)
{
int setting;

if ((DataBits < 5) || (DataBits > 8))
{
return (-1);
}

if ((StopBits != 1 && StopBits != 2))
{
return (-1);
}

if ((Parity != NO_PARITY) && (Parity != ODD_PARITY)
&& (Parity != EVEN_PARITY))
{
return (-1);
}

setting = DataBits - 5;
setting |= ((StopBits == 1) ? 0x00 : 0x04);
setting |= Parity;

outp(portbase + LCR,setting);

return (0);
}