I think I fried my OLED ... help diagnosing the cause & find a fix.

68gt500

New Member
after realizing, that I need a lot to learn (see my post "help an old fart Rallye Meter") I have been doing much more basic stuff and really enjoying it.

I have built a car Info center set that displays temperature via DS18B20 sensors, car battery voltage and RTC via DS1307. So far so good.
A GPS Module is on order to get altitude, speed and heading.

Output goes to 16x2 OLED which has been great, until yesterday when some wires got tangled and it stopped displaying new data.

On power reset it comes to life with my greeting message, but nothing arrives via serout.
Tried a 20m2 and also a 08m2 to send data - does not work.
Reprogrammed the 18m2 on the interface board - yes I did, but no improvement
Greeting messages can be changed - yes

I assume that the OLED is ok, probably the 18m2 also, since the the greeting message does display.

What should I try next? Not a lot of components on that interface board.

Ordering a new AXE132 - well yes, that would be the next step....

Any input appreciated
 

hippy

Technical Support
Staff member
I suspect there may be nothing actually wrong, just that any wires dislodged may have not been placed back where they should have been.

If the display is showing the welcome message then it would appear the display itself is not damaged, and if you can program the PICAXE-18M2 on the display driver board that would seem to be working as well.

So the issue would seem to be in receiving or with whatever is sending to it. You can test the serial input to the display board by running the program below with the AXE027 connected, manually taking the serial input high and low ...

Code:
#Picaxe 18M2
#Terminal 4800
Pause 2000
SerTxd( "Started", CR, LF )
Do
  If pinC.5 = 0 Then
    SerTxd( "0" )
    Do : Loop Until pinC.5 <> 0
  Else
    SerTxd( "1" )
    Do : Loop Until pinC.5 <> 1
  End If
Loop
If you can get 0's and 1's shown when the input pin is toggled, then you can set the output of whatever goes to it to toggle and see if that's the same.
 

68gt500

New Member
Update:
Wiring is ok. Double &tripple checked.
Code is:
Code:
#no_data
symbol oled = c.1 ; for the 08m2  - for the 20m2 I tried several B.7, C...
main:
Serout oled,N2400,(254,1)	;OLED clear
	Serout oled,N2400,(254,128,"Hello")
	Serout oled,N2400,(254,192,"World")
	pause 1000
	debug
	goto main
Checked the resistances:
The OLED Interface Input pin is shorted to ground. The one that goes to C5 on the 18m2. Removing the Picaxe it shows the correct 10K. So it seems the 18m2 is bad.

What Do you think?


@Hippy: With your code4: No, no reaction at all
@ Alan: Reprogramming the 18m2 on the board via the existing connector. With power applied.
 
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68gt500

New Member
I checked the diagram of the IF Board, these pins are unused:
symbol spare0 = C.0 ; spare output 0
symbol spare1 = C.1 ; spare output 1

could I reroute the input to either of them - just changing:
symbol RX = C.5 ; serial receive pin ---> to either c.0 or c.1 ??

What do you think?
 

hippy

Technical Support
Staff member
could I reroute the input to either of them - just changing:
symbol RX = C.5 ; serial receive pin ---> to either c.0 or c.1 ??
That should work but it is worth checking those pins with the earlier test code first.

One consequence of an electrically damaged pin on a PICAXE is that it may have also damaged other pins. Even if not it would be recommended to replace a PICAXE with an electrically damaged pin as there's no easy way to tell if further damage is being done or not.
 

68gt500

New Member
Using the spare pins seemed like such an good idea..

Sorry to say - no, it did not work - seems the 18m2 is fried beyond that one pin.

I´ll order a new 18m2...

Unless you have a better idea ;-)

Thanks for the help.
 

hippy

Technical Support
Staff member
Sorry to say - no, it did not work - seems the 18m2 is fried beyond that one pin.Thanks for the help.
That does seem a little odd because other pins on that port ( RAx on the native PICmicro ) do seem to be working or you could not reprogram it and wouldn't be able to control the OLED.

It's not easy to say what's going on being not able to look over your shoulder so a new 18M2 is probably the best way forward. If that also doesn't work it would point to some other issue or how you are testing, perhaps using wrong pins/contacts etc.

The data serial in on an AXE132 board is a hardware input only pin, and I imagine that would be harder to destroy than inadvertently shorting an output pin. There are only three wires to the board so hard to see how things getting tangled may have damaged it.

Forgive me if I'm wrong but I have a gut feeling that it's simply something you aren't doing right or are overlooking. It just seems odd that everything is working except for running the test code, pins on the port are working except the ones you want to use. Did you change pinC.5 to pinC.0/C.1/C.2 throughout the code ?
 

68gt500

New Member
Thanks hippy,

the wire tangling was a piece of wire that connected the 12V and 5V rails, as far as I can tell.

Yes I did search & replace on all the occurrences of the pins...

But maybe you are right.

I will sleep over it, do some testing and report back tomorrow evening.

Plan is to use a different, new project board with a new 08m2 that I have and just send out some basic strings to the oled.

I did order a new 18m2 and also a complete AXE132.

Good night
 

68gt500

New Member
Thanks fo the help.

A good nights sleep and a little time later:

not only is the receiving 18m2 toast, also the sending 20m2.
18m2: I can still access an reprogram - but nothing going in via C.5 or C.1 or C.0 - I will not waste any more trying other pins
20m2: Can not even connect to anymore - Hardware not found ... The board is okay, as an 08m2 is accessible and programmable

Waiting for order to come in...
 

premelec

Senior Member
You need to trace WHY the PICAXEs got killed or you will kill more of them - good luck... and put in some current limiting resistors in series with pins which may be getting too much current inadvertently.
 

newplumber

Senior Member
Hi
premelec is right ... who killed the picaxe? and why? although i say it 40+ times its very hard to do :) unless of course you use over whelming voltage
FWIW before I add power to any of my projects...I simply see if there is resistance between 5v and ground it saved me alot of smoke
 
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