DS18B20 on pin 3 08M

[rolsen]

Silicon Chip article Feb 06 page 63 shows DS18B20 connected to 08M pin 3.
Yet when I use "readtemp 3" command I get error "this command cannot be used on pin 3". Is this a circuit error?

 

[bgrabowski]

Leg 3 is pin 4 on a Picaxe 08. Could this be the problem?

 

[Technical]

Due to the internal PIC structure of input 3 (physical leg 4) it can only be an input. The 1 wire protocol required for the DS18B20 requires bidirectional signals.
Therefore the sensor cannot be connected to this leg - use pin1, 2 or 4 instead.

 

[manuka]

I don't have the SiChip article in front of me, but did you mean my Jan.2006 "Swan's Law" one? There's a Feb. article with a 7 seg LED thermo I recall. In any case the DS18B20 certainly does NOT go to the 08M "pin" 3 !

If it's my version then check pix/code =&gt; www.picaxe.orcon.net.nz/433rpt.jpg <A href='http://www.picaxe.orcon.net.nz/433rpt.jpg ' Target=_Blank>External Web Link</a>.

One of those recent articles had a schematic error - a link missing on the 22k/10k programming Rs too. I notified this some time back OK. Stan

Edited by - Stan. Swan on 2/8/2006 12:10:35 AM

 

[rolsen]

thanks all. confusion between pin &amp; leg in actual circuit diagram. Hi Stan, no not your article. Check the page indicated and you will see the problem.

 

[Michael 2727]

I am the culprit, I wrote the article.

I had not planned to tell the forum anything
until I had PCBs and Chips available in the
UK for enthusiasts to try out.

Everything should be sorted out within 2
weeks or so, fingers crossed.

The original draft mentioned the &quot;actual&quot;
and &quot;physical&quot; pin arrangement for picaxes
but it was culled in the edit.

And probably due to the previous tutorials
Silicon Chip has done on picaxes, was deemed
unnessesary, although it is drawn in the
schematic diagram showing both pin/leg.

Hope you have fun with it,,~ ;o)

Yes, they are swapped, I will let Silicon
Chip know, thank you,
Michael




Edited by - Michael 2727 on 2/8/2006 5:01:44 AM

 

[Michael 2727]

Rolsen, go here -
<A href='http://porepunkahps.vic.edu.au/home/jef01/display.htm ' Target=_Blank>External Web Link</a>
There is some basic code here to use.
Silicon Chip will have it available when they update their website as well.

 

[Michael 2727]

Turns out this was my fault,, ~ ;o(
The original schematic I sent Silicon Chip
had pin3/leg4 and pin4/leg3 swapped.
The DS18B20 and Switch inputs to the Picaxe
need to be swapped in the schematic, on page 63, Silicon Chip Feb 2006.

This is what happens at 3am and you've had
too much coffee.