Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!rutgers!ucsd!nosc!helios.ee.lbl.gov!ux1.lbl.gov!beard
From: beard@ux1.lbl.gov (Patrick C Beard)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Reading chars from serial port
Message-ID: <560@helios.ee.lbl.gov>
Date: 30 Jul 88 11:19:46 GMT
References: <77900004@peterson>
Sender: usenet@helios.ee.lbl.gov
Reply-To: beard@ux1.lbl.gov (Patrick C Beard)
Organization: Lawrence Berkeley Laboratory, Berkeley
Lines: 67

In article <77900004@peterson> peterson@peterson.applicon.UUCP writes:
>
>I want to read (at fairly high speed) characters from the serial port
>until I get a certain character. 
>
>Joe Peterson
>Schlumberger
>Billerica, Ma
>
>uucp:  ...mit-eddie!applicon!peterson

Here is how I do it:

/* serialhelp.c */

#include <SerialDvr.h>

SetUpPort(port,buf,length, inRefPtr, outRefPtr)
SPortSel port;	/* selector for which port to set up */
char *buf;
long length;
int *inRefPtr, *outRefPtr;
{
	/* decide which port to open -- port A is modem, B printer */
	switch(port) {
	case sPortA:
		error=OpenDriver("\p.AIn",inRefPtr);
		error=OpenDriver("\p.Aout",outRefPtr);
		break;
	case sPortB:
		error=OpenDriver("\p.BIn",inRefPtr);
		error=OpenDriver("\p.Bout",outRefPtr);
		break;
	}

	/* set up the speed of the buffers -- hardwired to 1200 baud here */
	SerReset(*outRefPtr,baud1200+stop10+data8+noParity);
	SerReset(*inRefPtr,baud1200+stop10+data8+noParity);
	
	/* set up the incoming buffer */
	SerSetBuf(*inRefPtr, buf, length);
}

/* non-blocking read of serial port */
ModemGetChar(inRef)
int inRef;	/* reference to the serial port */
{
	long count, bytes;
	char theChar;
	
	SerGetBuf(inRef,&count);
	
	if(count) {	/* if any characters, then read one of them */
		bytes=1L;
		FSRead(inRef,&bytes,&theChar);
	} else {
		theChar=0;	/* flag to indicate no character available */
	}

	return(theChar);
}

I hope this helps you.

Patrick Beard
Lawrence Berkeley Laboratory
beard@ux1.lbl.gov