RF TX/RX link w Ds18B20 trouble

P

pengoomeister

New Member
Hi,
I think I'am out of ideas and need some help with my code.
I have built TX and RX units which works when I run a simple test loop with LEDs connected. I've run the code in proteus and in the virtual terminal everything works, it also works on my veloboard connecting the PICs with a straight wire.
But in real life I have trouble getting a stable transmission, and my temperature from the TX unit is 0.0.

TX code
Code: 
'Symbol definitions
symbol TempRead = w0    '(b1:b0)
symbol TempC_100 = w1    '(b3:b2)
symbol Whole = b4
symbol Remainder = b5
symbol msb = b7

symbol STATIONID = $02

main:
    pause 5000
    high 2 'turn on DS18B20 temp sensor
    ReadTemp12 2,TempRead    'Read tube air temp
    low 2 'deactivate temp sensor
    Goto DoCal    'Calculate Temp
end

DoCal:
    msb = TempRead / 256 / 128    'Find most significant bit, 0 means a positive number.
    if msb = 1 then    '1 is a negative number
        TempRead = TempRead ^ $ffff + 1    'Twos comp for neg calc
    endif
    'Start 12 bit conversion
    TempC_100 =  TempRead * 6
    TempRead = TempRead * 25 / 100
    TempC_100 = TempC_100 + TempRead
    'End 12 bit conversion
    Whole = TempC_100 / 100    ' "/" returns whole number
    Remainder = TempC_100 // 100    ' "//" or "%" = modulus divide
    Remainder = Remainder / 10    'Reduces the amount of decimal places by one, but rounds down.

if msb = 0 then

positive:
high 1 'activate transmitter
pause 500
serout 4,T300,($55, $55, $55, B4, B5, B7, STATIONID)
low 1 'deactivate transmitter
pulsout 0,20000 ' red LED winks as data sent
goto main
endif

if msb = 1 then

negative:
high 1 'activate transmitter
pause 500
serout 4,T300,($55, $55, $55), B4, B5, B7, STATIONID
low 1 'deactivate transmitter
pulsout 0,20000 ' red LED winks as data sent
goto main
endif
RX code
Code: 
'Reciver code
'Symbol definitions
symbol Whole = b4
symbol Remainder = b5
symbol msb = b7
symbol STATIONID = b6

high 1 'activate reciver
pulsout 0,2000 ' red LED winks as data sent


rxloop:
serin 4,T300,Whole, Remainder, msb, STATIONID
pulsout 0,2000 ' red LED winks as data sent


if msb = 0 then

positive:
serout 2,T300,(#Stationid,";",#Whole,".",#Remainder,13, 10) 'DataLink
pulsout 0,20000 ' red LED winks as data sent
goto rxloop
endif

if msb = 1 then

negative:
serout 2,T300,(#Stationid,";","-",#Whole,".",#Remainder,13, 10) 'DataLink
pulsout 0,20000 ' red LED winks as data sent
goto rxloop
endif
 
E

eclectic

Moderator
I have made a start with the programs.

I used an AXE091 board.
08M (tx) HARDwired to 18X (rx)

T600 serout/serin

Code: 
'Symbol definitions
#picaxe 08M
symbol TempRead = w0    '(b1:b0)
symbol TempC_100 = w1    '(b3:b2)
symbol Whole = b4
symbol Remainder = b5
symbol msb = b7

symbol STATIONID = $02

main:
    pause 5000
    ;;;;;;;;
    ReadTemp12 2,TempRead    'Read tube air temp
    ;;;;;;;;
    Goto DoCal    'Calculate Temp
end

DoCal:
    msb = TempRead / 256 / 128    'Find most significant bit, 0 means a positive number.
    if msb = 1 then    '1 is a negative number
        TempRead = TempRead ^ $ffff + 1    'Twos comp for neg calc
    endif
    'Start 12 bit conversion
    TempC_100 =  TempRead * 6
    TempRead = TempRead * 25 / 100
    TempC_100 = TempC_100 + TempRead
    'End 12 bit conversion
    Whole = TempC_100 / 100    ' "/" returns whole number
    Remainder = TempC_100 // 100    ' "//" or "%" = modulus divide
    Remainder = Remainder / 10    'Reduces the amount of decimal places by one, but rounds down.

if msb = 0 then

positive:

serout 4,T600,($55, $55, $55, B4, B5, B7, STATIONID) 

sertxd(#B4, #B5,#B7,#STATIONID) ; for testing ****



pulsout 0,20000 ' red LED winks as data sent
goto main
endif

;;;;;;;;;;;;;;;
negative:

pause 500
serout 4,T600,($55, $55, $55, B4, B5, B7, STATIONID)

pulsout 0,20000 ' red LED winks as data sent
goto main
Code: 
'Reciver code
'Symbol definitions
#picaxe 18X
symbol Whole = b4
symbol REemainder = b5
symbol msb = b7
symbol STATIONID = b6

high 1 'activate reciver
pulsout 0,2000 ' red LED winks as data sent


rxloop:
serin 1,T600,($55,$55,$55),Whole, REemainder, msb, STATIONID ; No input 4 on 18x****

sertxd(#Stationid,";",#Whole,".",#REemainder,13, 10)
pulsout 0,2000 ' red LED winks as data sent


if msb = 0 then

positive:
serout 2,T600,(#Stationid,";",#Whole,".",#REemainder,13, 10) 'DataLink
pulsout 0,20000 ' red LED winks as data sent
goto rxloop
endif



negative:
serout 2,T600,(#Stationid,";","-",#Whole,".",#REemainder,13, 10) 'DataLink
pulsout 0,20000 ' red LED winks as data sent
goto rxloop
I hope it helps.
I have not had time to put in all the comments.


Welcome to the Picaxe Forum.

e
 

Attachments

Last edited:
hippy

hippy

Ex-Staff (retired)
This is most likely IMO to be down to the pre-amble, qualifiers and timing etc...

serout 4,T300,($55, $55, $55, B4, B5, B7, STATIONID)
serin 4,T300,Whole, Remainder, msb, STATIONID

Should become something like ...

serout 4, T300, ( "UUUUUUUUUUUUUUU" )
pause 10
serout 4, T300, ("XYZ", B4, B5, B7, STATIONID )

serin 4, T300, ("XYZ"), Whole, Remainder, msb, STATIONID
 
W

westaust55

Moderator
Last edited:
B

BeanieBots

Moderator
I'd go for transmitting the raw data and doing the conversion at the reciever end. That way there is less data to transmit.
 
M

MFB

Senior Member
Plotting

If you would like to plot and store data on a PC, download a free copy of StampPlot from www.selmaware.com. Includes simple examples (for Basic Stamp) of how to format the data and add a checksum.
 
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