755258c984
git-svn-id: https://svn.salfter.gotdns.org/svn/a2bfc/trunk@147 1b90f75b-8b96-4784-87c0-14078182fce6
73 lines
1.8 KiB
C
73 lines
1.8 KiB
C
/*
|
|
|
|
cc65 1-Wire Library
|
|
Copyright (C) 2003-2007 Scott Alfter (scott@alfter.us)
|
|
|
|
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, version 2.
|
|
|
|
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
|
|
*/
|
|
|
|
#include "ow-temp.h"
|
|
#include <errno.h>
|
|
|
|
short ow_temp_read(unsigned char* devid, unsigned char format)
|
|
{
|
|
unsigned char data[8];
|
|
static int lasttemp=-32767;
|
|
int newtemp;
|
|
int rawtemp;
|
|
unsigned char i;
|
|
|
|
if (!ow_temp_idcheck(devid))
|
|
{
|
|
errno=EINVAL;
|
|
return -1;
|
|
}
|
|
ow_selectdevice(devid);
|
|
ow_writebyte(68); // ask for a temperature reading
|
|
ow_wait(); // wait for operation to complete
|
|
ow_selectdevice(devid);
|
|
ow_writebyte(190); // retrieve the reading
|
|
for (i=0; i<8; i++)
|
|
data[i]=ow_readbyte();
|
|
|
|
rawtemp=((int)data[0]+((int)data[1]<<8));
|
|
errno=0;
|
|
switch (format)
|
|
{
|
|
case OW_TEMP_FAHRENHEIT:
|
|
newtemp=(rawtemp*9+8)/80+32;
|
|
break;
|
|
case OW_TEMP_CELSIUS:
|
|
newtemp=(rawtemp+8)>>4;
|
|
break;
|
|
case OW_TEMP_RAW:
|
|
default:
|
|
return (short)rawtemp;
|
|
}
|
|
/* 17 Aug 08: filter out garbage readings */
|
|
if ((newtemp-lasttemp>3 || newtemp-lasttemp<-3) && lasttemp!=-32767)
|
|
return (short)lasttemp;
|
|
else
|
|
{
|
|
lasttemp=newtemp;
|
|
return (short)newtemp;
|
|
}
|
|
}
|
|
|
|
unsigned char ow_temp_idcheck(unsigned char* devid)
|
|
{
|
|
return (devid[0]==40)?1:0;
|
|
}
|