I'm new to PBP and have been working with some DS18S20 and DS18B20 Sensors.
I'm using a PIC 16F877 here is my loop that reads the DS18S20. Is there a way
to detirmine if the sensor is a DS18B20 the on the Pin instead of a DS18S20?
Evidently the 18B20 requires a different routine to read an determine the temperature.
I get +22.06C on all 3 of the DS18S20 senors, but +152.87C and 152.81 on my DS18B20
sensors.


Thanks In Advance
Larry






DEFINE OSC 10 ' We're using a 10MHz oscillator
BAUD CON 84 ' N9600 for serial
CR CON 13 ' CR serial
LF CON 10 ' N9600 for serial LCD
SO VAR PORTC.6 ' Pin to for serial Out
SI VAR PORTC.7 ' Pin to for serial In
' Allocate variables
command var byte ' Storage for command
i var byte ' Storage for loop counter
sn var byte 'Polling Sensor Number
Rsn var byte 'Real Sensor Number
TempR var word ' Storage for temperature
TempS var word [12] 'Array To Store and send all Temps at one time
'DS1 var PORTB.0 ' Alias DS1820 data pin
'DS2 var PORTB.1 ' Alias DS1820 data pin
'DS3 var PORTB.2 ' Alias DS1820 data pin
'PORTB.3 is Reserved
'DS4 var PORTB.4 ' Alias DS1820 data pin
'DS5 var PORTB.5 ' Alias DS1820 data pin
'DS6 var PORTB.6 ' Alias DS1820 data pin
'DS7 var PORTB.7 ' Alias DS1820 data pin

'DS8 var PORTC.0
'DS9 var PORTC.1 ' Alias DS1820 data pin
'DS10 var PORTC.2 ' Alias DS1820 data pin
'DS11 var PORTC.3 ' Alias DS1820 data pin
'DS12 var PORTC.4 ' Alias DS1820 data pin
'PORTB.0 = 0-7
'PORTC.0 = 8-15

'*****DS1820 VARS AND SETTINGS*******
count_remain var byte 'DS1820 counter of remain bits
count_per_c var byte 'DS1820 counter per C bits
TempNeg var byte 'temperature sign -/+
TpNeg var byte [12] 'temperature sign -/+
'**********************************
SEROUT2 SO,BAUD, ["PIC Controller Ready",CR,LF]
sn = 0
Rsn =1
Main:

SEROUT2 SO,BAUD, ["Reading Sensor ",DEC Rsn,CR,LF]
i = 0
if sn = 3 then sn = 4
gosub Read_Temp

if i=10 then ErrX
if TempR=$FFFF then Error

TempS[Rsn-1] = TempR
TpNeg[Rsn-1] = TempNeg
'gosub Disp_Temp
sn = sn + 1
Rsn = Rsn + 1
if sn = 13 then
gosub Disp_AllTemp
sn = 0
Rsn =1
endif
TempR=$FFFF

pause 200
SEROUT2 SO,BAUD, ["========================================",CR, LF]
SEROUT2 SO,BAUD, [CR,LF]
goto Main
Read_Temp:

OWOut sn, 1, [$CC, $44] ' Start temperature conversion
waitloop1:
OWIn sn, 4, [count_remain] ' Check for still busy converting
If count_remain = 0 Then
pause 100
i = i + 1
if(i = 10)then return
goto waitloop1
endif
OWOut sn, 1, [$CC, $BE] ' Read the temperature
OWIn sn, 0, [TempR.LowByte, TempR.HighByte, Skip 4, count_remain, count_per_c]

if TempR = $FFFF then return
if (TempR.HighByte = $FF) and (TempR.LowByte <> 0) then
TempNeg = "-"
TempR = TempR ^ $FFFF
TempR = ((TempR >> 1)*100) - 25 + ((count_per_c + count_remain) * 100) / count_per_c
else
if (TempR.HighByte < $FF) and (TempR.LowByte <> 0) then
TempNeg = "+"
TempR = ((TempR >> 1)*100) - 25 + ((count_per_c - count_remain) * 100) / count_per_c
else
'************************************************
TempR=$0000 ' THIS IS ONLY NEED TO DEFINE !!!
'************************************************
endif
endif
return
Disp_AllTemp:
SEROUT2 SO,BAUD,[2,","]
for i = 0 to 11
if TpNeg[i] = "E" then
SEROUT2 SO,BAUD, ["TS",dec i+1,",E/R|"]
elseif TpNeg[i] = "N" then
SEROUT2 SO,BAUD, ["TS",dec i+1,",N/R|"]
else
SEROUT2 SO,BAUD, ["TS",dec i+1,",",TpNeg[i], DEC (TempS[i] / 100),".", DEC2 TempS[i], "C|"]
endif
TempS[i] = 0
TpNeg[i] = 0
next


SEROUT2 SO,BAUD,[CR,LF]

'SEROUT2 SO,BAUD, ["Raw", IBIN16 TempR,CR,LF]
'SEROUT2 SO,BAUD, ["---------------------------------" ,CR,LF]

return
Error:
SEROUT2 SO,BAUD, ["ERROR - Reading Sensor:", dec Rsn ,CR,LF]
TempS[Rsn-1] = 0
TpNeg[Rsn-1] = "E"
sn = sn + 1
Rsn = Rsn + 1
if sn = 13 then
sn = 0
Rsn =1
endif

goto Main
ErrX:
' "!!!ERROR!!!", $fe, $C0, "Reading Temp."
SEROUT2 SO,BAUD, ["Sensor: ",dec Rsn," Not Reporting" ,CR,LF]
TempS[Rsn-1] = 0
TpNeg[Rsn-1] = "N"
sn = sn + 1
Rsn = Rsn + 1
if sn = 13 then
sn = 0
Rsn =1
endif
goto Main

end