Problem interfacing AXE133 LCD with 18M2 Project Board

jproehl

New Member
Nothing is going to work until you get the LCD firmware back into the 18M2 chip on the back of the LCD. Use the program here http://www.picaxe.com/downloads/axe133.bas.txt.

After that always program the chip on the CHI030, not the one on the LCD.

Then check the soldering carefully, the solder is very sparse on the connections (LCD side) in the photo and it may be that you need to add a bit more solder on a few joints to get a good connection.

You can disconnect the serial pin completely, just leaving power - you should still get a welcome message when the contrast is adjusted correctly.
Hi:

I too am a newbie and I'm having a very similar problem trying to get a PICAXE20X2 to drive a 16x2 LCD, but I've wired mine up to operate in 4 bit mode. I hope this is an okay place to jump in with this problem, but please let me know if I should start a new thread instead.

My data pins B.2-B.5 are connected to DB4-DB7, respectively , B.0 is connected to RS and B.1 is connected to ENABLE. I've tried to code up the simple example from the PICAXE manual (modifying it for my different pin connections) and also just get a line of square blocks on the LCD. But my square blocks appear only on the second line of the LCD. If you think I'd be better served by using the code you provided on this thread, please let me know how I would need to change it to match with my pin set-up.

I've attached my code and a photo of the LCD. In the initialization subroutine you'll see a somewhat non-standard approach of shifting the two nibbles to match with the pin locations (i.e. so that the digits in each nibble map to the appropriate pins B.2-B.5). Hopefully it won't be too confusing, but I need to stick with this arrangement because once I get this to work, the PICAXE chip is going to pop into another circuit board that is hard wired with that pin usage. I've walked through the simulate function in the PICAXE editor watching the pins go high and believe that the proper pins are being activated. But, since the code is not working it could be a source of the problem.

I have my PICAXE20X2 mounted to an AXE118 board and I've added 8 pin headers to the 16 data pins on the two sides of the PICAXE20x2 to interconnect things. Let me know if you need to see a photo of that or anything else. I've also wired an off board 10Kohm potentiometer to adjust the backlighting for contrast adjustment of the LCD - that seems to work fine.

I'd appreciate any help anyone can provide as I'm totally lost at this point. Thanks!!
 
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