Axe 033 Lcd

[robbyraven]

Hi everyone,

I'm trying to interface the AXE 033 LCD with my 18X project board.

I've put a jumper across J2 so I can use the same 4.5V as the project board.
When I apply power and short the CLK terminals, I get

serial/ i2c lcd
00/00/00 00:00

which is correct I think. However, when trying the sample program from the datasheet (yes, after removing the CLK jumper), I get either nothing, or just

00/00/00 00:00

The datasheet says I have to work directly from the picaxe pin, not the buffered outlet from the project board. How do I do this? So far I have been pressing the end of a bar wire against the exposed section of the relevant pin according to the pinout diagram (i.e. top right for serout 7, bottom right for serout 0).

Just to be clear, when I check the display with the CLK jumper, it's fine. I then, remove power, remove CLK jumper. Re-apply power, blank screen. Touch the wire from 'in' on the LCD module to output 0 or 7 (I've tried both, adjusting the sample program code accordingly), and I get either nothing or all those zeros. Press reset, on the project board to restart the program whilst the output is already in place, no difference, I just get blank screen or zeros.

Help?

 

[eclectic]

Robby, re. connecting

Two possible alternatives.

Carefully remove the ULN2803 chip, and then use a wire
directly inserted into the socket.
However, this could cause problems if you also need the Darlington.

A more permanent alternative

The program on page 8 of the AXE033 datasheet,

init: pause 500 ‘ wait for display to initialise
main: serout 7,N2400,(254,128) ‘ move to start of first line
serout 7,N2400,(“Hello!123”) ‘ output text
end

Change it to

init: pause 500 ‘ wait for display to initialise
main: serout 0,N2400,(254,128) ‘ move to start of first line
serout 0,N2400,(“Hello!123”) ‘ output text
end

Now, there is a “hidden” direct connection to output0,
Near the bottom right of the CHI030 board, are three connection pads.
One of them is connected to output 0.

It's shown on page 7 of the CHI030 datasheet,
but is not shown on the other diagrams on the datasheet.

After VERY carefully checking, with a multimeter,
you could solder a wire, or better, solder in a turned pin socket.

e

 

[Technical]

Bottom right of which chip - on either it is not output0?...

You need to have the wire permanently connected to be able to test correctly. Output0 is actually connected directly to a test pad, the unmarked row of three holes bottom right. Use the hole nearest the 'PIC WWW' text.

 

[eclectic]

Sincere apologies. I'll edit my previous post.
e

 

[robbyraven]

Perfect

Thanks a lot guys, I used the top one of the three test pad holes and it worked straight of the bat. What efficient problem solvers there are here!

I doubt if you've heard the last of me,

Thanks again,

Rob

 

[eclectic]

NOT a recommendation, but, just a few thoughts.

If you need a dedicated output 7.

Remove the 18 leg ULN2803 chip.

Replace with a 16 leg ULN2003, correct way up,
leaving the “top” two socket holes free.

Add a 1K (one thousand Ohm) resistor, across sockets 1 and 18.

I've just tried this, using a CHI030 and an AXE033.
Two power supplies, 4 x NiMh AA each.
AXE033 supplied from the board.

#picaxe18X

init: pause 500 ‘ wait for display to initialise

main: 
for w0 = 1 to 65000
serout 7,N2400,(254,128) ‘ move to start of first line

serout 7,N2400,(#w0) ‘ output text
pause 200
next

It's my Picaxe, and if I blow it, it's MY fault.
It hasn't so far.

I repeat. Just for MY experiment!


e. (and OE)

 

[robbyraven]

Good thinking, good idea.

I think what I really need to do is to 'take off the training wheels' and start building circuits without the project board at all. I've got the circuit diagram of the 18X project board, so it ought to be simple enough to recreate the same project on a breadboard and then PCB.

Thanks again for your help- I'm seriously impressed by the capability of the picaxe and the support offered on the forum. I already have more projects in my head than I will ever find time to build!