Read DS18S20

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- 18th September 2008, 16:44
PICante

Read DS18S20

Hi all.

Short time ago I found this code posted by CocaColaKid “ReadDS18S20” in this thread: http://www.picbasic.co.uk/forum/show...hlight=DS18S20
Very neat I thought until I discovered that the STR function is not supported for 16FXXX, too bad. I have searched and found other pieces of code but they all seems to have a different approach to the task and I felt I could understand this code better. The PBP manual is not very helpful on OW and my question is what do I need to be change (and why) in this code to make it compile for the 16F688?

Thanks!
- 18th September 2008, 17:09
skimask

Quote:

Originally Posted by PICante

Very neat I thought until I discovered that the STR function is not supported for 16FXXX, too bad

Double check your manual...and compare what it says to the datasheet for the 16F688.
'cause it looks to me like everybody in that other thread is using a 16Fxxxx series PIC and nobody is using an 18F.
- 18th September 2008, 17:38
PICante

Hi skimask!

Sorry, I’m somewhat confused here I don’t know what to believe in (of curse I believe in you!) since I also got a compilation error saying: “ERROR: Macro OWINSTR?W not found in macro file.”

Huuh?

Edit: Hey… it’s the other way around, it says 12-bits not supported! (found my glasses) :-) . Then (as usual) I must be doing something else wrong!
- 18th September 2008, 17:48
skimask

Quote:

Originally Posted by PICante

since I also got a compilation error saying: “ERROR: Macro OWINSTR?W not found in macro file.”

The latest PBP update should fix that problem.
If not, there's a thread somewhere around here relating a problem similar to that..somewhere...

Quote:

Edit: Hey… it’s the other way around, it says 14-bits not supported! (found my glasses) :-) . Then (as usual) I must be doing something else wrong!

I don't know which manual you're reading.
My manual says 12-bits aren't supported using the REP and STR modifiers. I'd tend to believe that due to the stack/ram constraints of 12 bit devices.
- 18th September 2008, 17:55
PICante

Yes, my manual also says 12-bit. edited almost instantaneously! :-)

I have got the P250a patch installed, can’t seem to find any newer?
- 18th September 2008, 17:57
skimask

Quote:

Originally Posted by PICante

Yes, my manual also says 12-bit. edited almost instantaneously! :-)

I have got the P250a patch installed, can’t seem to find any newer?

There's a b patch out now.

Show the code...
- 18th September 2008, 18:03
PICante

I will try to find and run the patch to find out if that’s the culprit.

Thanks ski
- 18th September 2008, 19:20
PICante

Patch in place..... No, that did not cancel the compile error!
Here’s the code:

Code:

READTEMP: OWOUT PORTA.5,1,[$CC, $44] ' SEND Start Temperature Conversion command OWOUT PORTA.5,1,[$CC, $BE] ' SEND Read Temperature command OWIN PORTA.5,0,[STR dq\9] ' Retrieve all 9 bytes of data RawTemp.Byte0 = dq[0] RawTemp.byte1 = dq[1] IF RawTemp.8 = 1 then ' Check IF temperature is a negative reading SignC = Negative RawTemp.lowbyte = RawTemp.lowbyte ^ 255 ' Invert data ELSE SignC = Positive ENDIF dummy = RawTemp.0 ' Store the half degree indicator bit TempC = ((RawTemp.lowbyte) >> 1) * 100 ' Divide raw data by 2 to give real temperature TempC = TempC + (dummy * 50) ' Add the half degree is present IF SignC = Negative then ' Only proceed IF temperature is negative IF TempC => 1770 then SignF = Negative TempF = (TempC + 5000) * 900 TempF = div32 500 TempF = TempF - 12200 RETURN ELSE SignF = Positive TempF = (TempC + 5000) * 900 TempF = div32 500 TempF = 12200 - TempF RETURN ENDIF ENDIF SignF = Positive TempF = TempC * 18 / 10 + 3200 RETURN

Thanks!
- 18th September 2008, 19:44
Acetronics2

Hi,

Is not that much simpler than yout modifyer and the two following lines :

Code:

OWIN PORTA.5,0,[STR dq\9] ' Retrieve all 9 bytes of data RawTemp.Byte0 = dq[0] RawTemp.byte1 = dq[1]

( taken from a Malc C example )

Code:

OWIN Porta.5, 2, [R_Temp.Lowbyte, R_Temp.Highbyte] ' Read two bytes / end comms

Alain
- 18th September 2008, 21:38
PICante

Hi Alain,

Your suggestion tested, does not compile due to multiple errors in the line.

Made a search in the forum but could not find anything regarding the STR macro problem.

Thanks.
- 18th September 2008, 22:51
skimask

I know that's not ALL of the code...
- 19th September 2008, 09:12
Acetronics2

Quote:

does not compile due to multiple errors in the line.

Made a search in the forum but could not find anything regarding the STR macro problem.

I can't believe it ...

I can't ...

Alain
- 19th September 2008, 10:43
PICante

Quote:

Originally Posted by skimask

I know that's not ALL of the code...

You are correct; it’s not all the code. The rest of the code is working fine this is only going to be the part (subroutine) to measure temperature. And it’s also the part that does not compile.

Thanks!
- 19th September 2008, 10:58
Bruce

Looks like you have dq defined as a WORD VS BYTE.
- 19th September 2008, 12:37
skimask

Quote:

Originally Posted by PICante

You are correct; it’s not all the code. The rest of the code is working fine this is only going to be the part (subroutine) to measure temperature. And it’s also the part that does not compile.

Thanks!

The rest of the code may very well be working fine, but the rest of the code also has any setup/initialization/interrupts that you are using, therefore, is just as important as the code that's messing up.
I must be making this up as I go or something...
- 19th September 2008, 14:34
CocaColaKid

We need to see how the variables are declared as well as other settings. Its obviously not this part of the code that is the culprit because it compiles fine for others which means there is a problem somewhere else in the code. Like Bruce said, it could be something simple like a word variable being declared as a byte.
- 15th October 2008, 19:31
PICante

Hi Guys!

Been busy doing other stuff but now I’m back to finish this project! As some of you suspected it was a “simple” mistake, a word variable was declared as a byte! Now it runs like clockwork!
It seems the problem is always simple, finding the problem is the hard part!

Thank you all!