Problem with AXE033 LCD

M

msx

New Member
Hello, i'm trying to use the AXE033 board with the LCD display. I'm using i2c interface, but it doesn't seem to work.
I've followed the instruction: added both J1 and J2 jumpers, regulated contrast etc. I've tryed the sample code to show Hello but nothing :(

One thing is that when i connect power, the first line show all black (ie, all dots are black on all characters). The manual says it should show the time/date or 00/00/00 00:00 if not using a clock (my case). Can it be that my soldering has short circuited some pins ? any other idea ?

Many thanks
 
T

tarzan

Senior Member
This could be the result of the instructions that you sent it. Please post your code exactly as used.

Could be a hardware issue remembering that only one set of pull-up resisters (already on AXE033) are required and the AXE033 will take 500ms to initialize.

I take it that you don’t have a DS1307 in its socket or battery. Nor should you have the CLK jumper fitted.

Can you show us picture of your soldering?
 
M

msx

New Member
The code is exacly the one on the example, altho i tried making some difference (ie longer start pause).

Code: 
init: pause 500 ‘ wait for display to initialise
i2cslave $C6,i2cslow,i2cbyte ‘ set up i2cslave for LCD
main: writei2c 0,(254,128,255) ‘ move to start of first line
pause 10 ‘ wait for LCD to process data
writei2c 0,(“Hello!123”,255) ‘ output text
end
I don't think it's the code, the LCD is not showing the time/date when powered up like the docs says.

I didn't added pullup resistors, the AXE033 doc says they're already there..
I'll take a picture this evening.. The soldering is maybe not the best but it looks like there's enought distance between pins.. also, i passed a small blade just in case some solder was contacting (i hope this wasn't a bad move :))

Indeed, no DS1307 nor battery.

Thanks!
 
W

westaust55

Moderator
Cannot see anything wrong with your program - its as per the manual.

Note the AXE033 only displays the time IF you have the clock jumper installed across the two terminals "CLK" (see top of page 5 in the manual)

With the CLK link in place it shows a clock display n the second line and will not respond to serial or i2c communications. It also displays the first stored message (if there is one) on the top line.

If you have that link in and no DS1307 clock chip I have no idea what might be displayed.
 
W

westaust55

Moderator
Might have solved your problem.

may not look different but try this code:

Code: 
init: pause 500 ‘ wait for display to initialise
i2cslave $C6,i2cslow,i2cbyte ‘ set up i2cslave for LCD
main: writei2c 0,(254,128,255) ‘ move to start of first line
pause 10 ‘ wait for LCD to process data
writei2c 0,("Hello!123",255) ‘ output text
end
When I pasted into the Program Editor found your quote marks (") are not the correct ones. Likely to do with your keyboard
 
T

tarzan

Senior Member
As I said before no CLK jumper. The clock will only work in serial mode i.e. no J1 jumper.

8. Connect a power supply to the main connection header (red wire to V+, black
wire to 0V). The LCD should display a time message when the two CLK
contacts are shorted (e.g. with the jumper provided in the kit) and once the
contrast is adjusted (via the variable resistor marked ‘contrast’). If the LCD
does not display a message check the power, contrast and the 14 connector pins
carefully. (Note that if the optional clock upgrade chip is not fitted, the time
will always show as 00/00/00 00:00)
Click to expand...
In i2c mode the LCD module acts as a ‘dumb’ i2c slave device. The clock and alarm
functions are not available - all clock and alarm functions must be carried out by
the PICAXE X part itself.
Click to expand...
 
M

msx

New Member
Ok, thanks guys, you sure are helpful!
westaust55, my quotes were correct, those wrong one was becouse i copy/pasted here from pdf. I substituted them with correct one before compiling.

About the time/date: you are right, i was not using the CLK jumper. This explains why it doesn't show the time.
I'll try this evening removing the I2C jumper, putting it in the CLK and connecting only the power, as per manual it should show all zeroes. This would hopefully exclude any soldering issue :)

In other case there must be something either in the soldering, in the wiring or the LCD is somehow broken..
 
T

tarzan

Senior Member
J1 & J2 jumpers

That sounds like a good plan.
If you have some handy you could put headers & pins in J1 & J2 locations. I put a row of six pins across them cutting the middle two bottom side pins short. This then gives you a parking spot for the jumpers when not in use.
 
M

msx

New Member
Ok, tried it and it don't work.. I closed the clock jumper and it still shows all black characters.
Unfortunately, my brother took our digital camera so i couldn't take pictures.
I tested the pin with a meter and discovered that three pins are connected (they show 0 resistance). That's strange becouse the soldering looks very spaced.

I used a strip like this the black plastic in contact with the board.. Is it possible that some solder sneaked back there, between the plastic and the board ? It sounds very strange to me but i can't find another explanation..
 
I

inglewoodpete

Senior Member
Black characters on an LCD suggest that the contrast is turned up too high. Have you tried to turn the contrast pot down while the 'black boxes' are showing?
 
W

westaust55

Moderator
One thing is that when i connect power, the first line show all black (ie, all dots are black on all characters).
Click to expand...
Is this also true if you power up the AXE033 without a CLK link installed and without the PICAXE connected?
 
W

westaust55

Moderator
I used a strip like this the black plastic in contact with the board.
Click to expand...
That type of header strip is exactly what I was supplied with for the connection between the two boards and for the connections on the rear of the control board.


When looing at the rear of the AXE033 controller board with the i2c connections to the right, which 3 pins are showing as shorted together – that is zero resistance between them.
Cannot test one myself until later this evening but others may get a chance in advance of me.
 
M

msx

New Member
uhm i don't took the numbers, sorry.. They were almost in the middle. If you're so kind to check with one of your boards and find 3 pins shorted that means they're ok on my board too..
but that seems strange to me, if they're connected than why making 3 different pin ? :p
looks like i'll need to separate the two boards and de-solder the pins.. probably breaking everything..
 
W

westaust55

Moderator
Desoldering to separate the two boards would have to be done carefully.
Someone else tried that recently and then indicated they overheated the tracks and pads at the holes causing them to lift of the board.

IF you have to go that route may be safer to cut the pins carefully and then remove the halves from each board one at a time rather than trying to get them all free first.
 
W

westaust55

Moderator
Just measured the same as Tarzan with LCD connections 1, 5 7, 8,9 and 10 all to earth.

In fact its exactly like the diagram in the PICAXE manual 3 pages 34/35 in terms of Vdd (5V), 0V and the contracts pot.

So if you only have 3 pins shorted then that may be the source of the error as the must be a group of 4 (7 to 10) shorted together.
 
E

eclectic

Moderator
msx.

Firstly, follow the suggestions given by Tarzan and Westaust.

Then, as another test, try your AXE033 in SERIAL mode.
Using the Axe033 Datasheet.

1.Unsolder or disconnect the J1 link. (P.3 no. 4)

2.Using the program on page 8 as a basis for the test.

Just use V+, 0, and IN on the LCD
Choose your own output pin on the Picaxe.

I used pin 0 on a 28X1

Code: 
#picaxe 28x1

init: 
serout 0, n2400,(254,1) ; clear display

pause 50 ‘ wait for display to initialise

main: 
serout 0,N2400,(254,128) ‘ move to start of first line

serout 0,N2400,("Hello") ‘ output text


serout 0,N2400,(254,192) ‘ move to start of second line

serout 0,N2400,("World") ‘ output text
 
M

msx

New Member
My setup is about like this (sorry for the programmer art):



westaust55 said:
Just measured the same as Tarzan with LCD connections 1, 5 7, 8,9 and 10 all to earth.

In fact its exactly like the diagram in the PICAXE manual 3 pages 34/35 in terms of Vdd (5V), 0V and the contracts pot.

So if you only have 3 pins shorted then that may be the source of the error as the must be a group of 4 (7 to 10) shorted together.
Click to expand...
Uhm sorry that's a little obscure to me (have patience, i'm just starting now :)).. That means that i could have a pin that doesn't make contact with the board? uhm that's strange, i've put quite a lot of solder (indeed, probably too much).

Anyway this could be the reason.. I'll try asap. Unluckly i'll be on vacation from tomorrow so i'll probably try after half august.. In the meantime thanks everybody for your great support!
 
T

tarzan

Senior Member
Dry solder joint? No offence to you but if your soldering skills are not up to the task, you may have a joint that looks ok but is not passing any current. This might happen if not enough heat was applied during soldering or a flux failure to name a few. You could try re-flowing the solder with the soldering iron but be careful not to cook the adhesive off the underside of the PCB tracks lifting them and doing permanent damage. If you have too much solder on the joints try solder wick it works a treat.
 
M

msx

New Member
tarzan said:
Dry solder joint? No offence to you but if your soldering skills are not up to the task, you may have a joint that looks ok but is not passing any current. This might happen if not enough heat was applied during soldering or a flux failure to name a few. You could try re-flowing the solder with the soldering iron but be careful not to cook the adhesive off the underside of the PCB tracks lifting them and doing permanent damage. If you have too much solder on the joints try solder wick it works a treat.
Click to expand...
Uhm that's very possibly true.. I'm not very skilled at soldering, and i must admit to have broken some of the golden rules of this art.. Also i have a very old iron with a relatively big point.

Well i think we've isolated the problem.. Sorry if this was a stupid mistake!
 
M

Mycroft2152

Senior Member
Most solder has a bit of "flux" in the core. Sometimes this isn't enough. Yu need to add more. Buy a small container of solder flux and brush it on the components before soldering. You'll get nearly 100% reliable solder joints.

Flux helps wet out (breaks the surface tension) the solder joint and the solder flows easily.

Myc
 
M

msx

New Member
Ok thanks.. I'll go and buy some flux. Btw how do you apply it to the holes?

Also since i'm here, i've just read this article:

http://dragon.herts.ac.uk/~eleqdml/teaching/general/soldering/

Now i've been carefull not to have "balls" of solder, my joints are all distended on the board around the pin.. Is it still possible that it doesn't connect like in the first example on the "Common faults" paragraph? This sound strange to me
 
M

Mycroft2152

Senior Member
I usually just brush the flux on after I have placed the component in the holes. There are flux "pens" availible too.

It sounds like you have a "dry" solder joint. It is not that unusual. Use a solder sucker and or a solder braid to remove the excess solder, then flux and resolder.

Good Luck, you are almost there.

Myc
 
T

tarzan

Senior Member
The tip size of your iron is also in question. It should be small enough to do each pad individually without touching any adjacent pads.
 
Last edited:
M

msx

New Member
ok guys :p I've just corrected my solderings and it works now! :) Probably one or more pin wasn't working..

Thanks everybody!
 
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