iButton isn't being detected.

[jopooze]

For my electronics project I require an iButton to be detected and differentiated from another iButton. I have 2 DS1990R iButtons running with an 18M2 Pic on the AXE091U. I created a BASIC program which worked originally but then stopped later. The program is below and was created simply to see if the buttons would be detected.

Start:
let b6 = 0
let b7 = 0
let b8 = 0
let b9 = 0
let b10 = 0
let b11 = 0
let b12 = 0
let b13 = 0

Loop1:
readowsn B.1
if b6<> 0 then high b.0 endif
if b7<> 0 then high b.0 endif
if b8<> 0 then high b.0 endif
if b9<> 0 then high b.0 endif
if b10<> 0 then high b.0 endif
if b11<> 0 then high b.0 endif
if b12<> 0 then high b.0 endif
if b13<> 0 then high b.0 endif
Goto Loop1

No matter what, the iButton shows no signs of being detected.

I'm very confused and have spent a lot of time trying to figure out what is going on. I have used programs from the Picaxe website itself (The manuals and Pdf's) amongst user submitted programs which apparently work for them.

Thank you for any response.

 

[erco]

If it worked before and doesn't now, you changed either your hardware or software. Have another look at both.

It's pretty bulletproof to read ibuttons using the code provided in the PDF at http://www.picaxe.com/docs/axe109.pdf

Per technical, use debug to quickly display your ibutton's serial number: http://www.picaxeforum.co.uk/showthread.php?27649-Sertxd-Hex-Formatter

 

[Technical]

Check the pull up resistor on the probe (in turn connected to B.1), is it pulled up to 5V?

 

[jopooze]

Thanks a lot for the responses. Tech hit the nail on the head. I was dumb and didn't put a resistor in thinking the board would miraculously do it for me xD. I grabbed a resistor from my teach and got it working.