ds1820.c

myTemp is used to connect PalmOS PDAs to Dallas Microlan(tm) Devices. It currently supports DS1820

/*
  myTemp is used to connect PalmOS PDAs to Dallas Microlan(tm) Devices.
  It currently supports DS1820/DS18S20 Digital Thermometers
  Copyright (C) 2000 Christof Klaiber

  This program is free software; you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free Software
  Foundation; either version 2 of the License, or any later version.

  This program is distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
  PARTICULAR PURPOSE.  See the GNU General Public License for more details.

  You should have received a copy of the GNU General Public License along with
  this program; if not, write to the Free Software Foundation, Inc., 59 Temple
  Place, Suite 330, Boston, MA  02111-1307  USA


  Christof Klaiber <[e-mail]>
  Lachnerstr. 22
  76131 Karlsruhe
  Germany
*/
#include <PalmOS.h>

#include "com.h"
#include "ds1820.h"
#include "onewire.h"

UInt32	DSDispatchTouchByteErr(Err);
UInt32	DSDispatchTouchResetErr(Err);

UInt32 DSDispatchTouchByteErr(Err err)
{
	UInt32	dsErr;
	
	switch (err)
	{
	case 0:
		dsErr = tempNoError;
		break;
	case serErrTimeOut:
		dsErr = tempSerErrTimeOut;
		break;
	case serErrLineErr:
		dsErr = tempSerErrLineErr;
		break;
	default:
		ErrDisplay("unknown error in touch byte");
		dsErr =	tempErrUnknownErr;
		break;
	}
	return dsErr;
}

UInt32 DSDispatchTouchResetErr(Err err)
{
	UInt32	dsErr;
	
	switch (err)
	{
	case 0:
		dsErr = tempNoError;
		break;
	case serErrBadParam:
		ErrDisplay("invalid parameter");
		dsErr = tempSerErrBadParam;
		break;
	case serErrNotOpen:
		ErrDisplay("serial port not open");
		dsErr = tempSerErrNotOpen;
		break;
	case serErrTimeOut:
		dsErr = tempSerErrTimeOut;
		break;
	case serErrLineErr:
		dsErr = tempSerErrLineErr;
		break;
	default:
		ErrDisplay("unknown error in touch reset");
		dsErr = tempErrUnknownErr;
		break;
	}
	return dsErr;
}

UInt32 DSReadScratchpad(UInt16 serialRefNum, UInt8 scPad[kScratchPadLength]) {
	UInt8	x;
	UInt8	crc;
	UInt8	exOrResult;
	Err		err;
	UInt8	character;
/* CRC table for Dallas 8-bit CRC calculations from App Note #27 */
	UInt8 crc_table[] = {
		0, 94,188,226, 97, 63,221,131,194,156,126, 32,163,253, 31, 65,
		157,195, 33,127,252,162, 64, 30, 95,  1,227,189, 62, 96,130,220,
		35,125,159,193, 66, 28,254,160,225,191, 93,  3,128,222, 60, 98,
		190,224,  2, 92,223,129, 99, 61,124, 34,192,158, 29, 67,161,255,
		70, 24,250,164, 39,121,155,197,132,218, 56,102,229,187, 89,  7,
		219,133,103, 57,186,228,  6, 88, 25, 71,165,251,120, 38,196,154,
		101, 59,217,135,  4, 90,184,230,167,249, 27, 69,198,152,122, 36,
		248,166, 68, 26,153,199, 37,123, 58,100,134,216, 91,  5,231,185,
		140,210, 48,110,237,179, 81, 15, 78, 16,242,172, 47,113,147,205,
		17, 79,173,243,112, 46,204,146,211,141,111, 49,178,236, 14, 80,
		175,241, 19, 77,206,144,114, 44,109, 51,209,143, 12, 82,176,238,
		50,108,142,208, 83, 13,239,177,240,174, 76, 18,145,207, 45,115,
		202,148,118, 40,171,245, 23, 73,  8, 86,180,234,105, 55,213,139,
		87,  9,235,181, 54,104,138,212,149,203, 41,119,244,170, 72, 22,
		233,183, 85, 11,136,214, 52,106, 43,117,151,201, 74, 20,246,168,
		116, 42,200,150, 21, 75,169,247,182,232, 10, 84,215,137,107, 53
	};

	
	character = 0xbe;
	err = OWTouchByte(serialRefNum, &character); 
	if (err)
	{
		return DSDispatchTouchByteErr(err);
	}
		
	for(x = 0; x < 9; x++) {
		character = 0xff;
		err = OWTouchByte(serialRefNum, &character);
		if (err)
		{
			return DSDispatchTouchByteErr(err);
		}
		scPad[x] = character;
	}
	
	err = OWTouchReset(serialRefNum, &character);
	ErrNonFatalDisplayIf(character == 0, "no 1-Wire device found");
	if (err)
	{
		return DSDispatchTouchResetErr(err);
	}
	if (!character)
	{
		return tempOWErrNothingDetected;
	}
	
	crc = 0;
	
	for(x = 0; x < 9; x++)
	{
		exOrResult = crc ^ scPad[x];
		crc = crc_table[exOrResult];
	}
	if (crc)
	{
		return tempErrCRCErr;
	}
	
	return err;
}

UInt32 DSReadTemperature(UInt16 serialRefNum) 
{
	Err		err;
	UInt8	character = 0x44;

	err = OWTouchByte(serialRefNum, &character);
	if (err)
	{
		return DSDispatchTouchByteErr(err);
	}
	
	return err;	
}

UInt32 DSResetTemperature(UInt16 serialRefNum)
{
	Err		err;
	UInt8	character;
	
	err = OWTouchReset(serialRefNum, &character);
	ErrNonFatalDisplayIf(character == 0, "no 1-Wire device found");
	if (err)
	{
		return DSDispatchTouchResetErr(err);
	}
	if (!character)
	{
		return tempOWErrNothingDetected;
	}

	return err;
}

UInt32 DSSkipROM(UInt16 serialRefNum) {
	Err	err;
	UInt8	character;
	
	err = OWTouchReset(serialRefNum, &character);
	ErrNonFatalDisplayIf(character == 0, "no 1-Wire device found");
	if (err)
	{
		return DSDispatchTouchResetErr(err);
	}
	if (!character)
	{
		return tempOWErrNothingDetected;
	}
	
	character=0xcc;
	err = OWTouchByte(serialRefNum, &character);
	if (err)
	{
		return DSDispatchTouchByteErr(err);
	}
	return err;
}