Problem interfacing AXE133 LCD with 18M2 Project Board

[si_90]

Hi all, apologies if this has been cleared up in a previous thread I have searched but are still having problems.

I have recently purchased the AXE133 Serial LCD for use in my project at college. I have followed the instructions and soldered the LCD as advised.
I am using a CHI030B 18M2 Project Board which I am powering through a 5V PSU which is connected to my breadboard.
Using the H2 connections on the LCD, I am connecting the V+ and 0V to the power rails of the breadboard, this is also shared with the Project Board.
Rightly saying as the LCD is powered up I should see a welcome message, regardless if it is receiving and output or any code from the Project Board.... which I am not.
I have checked the respective voltages and tried to alter the 10K contrast potentiometer, when I turn the contrast up full I see black rectangles.
At first I entered this simple program to read hello, however I changed the output pin used from B.7 to C.7 due to the Darlington Chip array on the Project Board.

init: pause 500 ; wait for display to initialise

main:
serout C.7,N2400,(254,128) ; move to start of first line
serout C.7,N2400,("Hello!123") ; output text

At the first attempt I downloaded the data to the 18M2 on the project board using the USB jack. To no avail, I inserted the USB jack into the LCD and tried to download the program to the 18M2 on the LCD which downloads successfully, suggesting correct positioning of the 18M2. Still nothing. I think I may have overwritten the code of the welcome message but should still see the Hello message.

Am I missing something major? Apologies again if this has already been cleared up as I am a newbie to Picaxe. I look forward to hearing from you.

Thanks a lot in advance.

Steven

 

[nick12ab]

Welcome to the PICAXE Forum.

The PICAXE-18M2 on the AXE133 PCB is used to convert the serial interface to the parallel interface, so you will need to reprogram it with the AXE033 Firmware if you want to use it as a serial LCD.

You should see the Welcome message on the display of the AXE133 regardless of whether or not it's connected to the project board.

Are the black squares on one line or two? One line means the LCD hasn't been initialised properly using the parallel interface, so check the connections on the 16-pin connector carefully. The PICAXE-18M2 on the AXE133 PCB must also be programmed with the correct code for the LCD to be initialised.

Please provide clear photographs of your project setup.

 

[si_90]

Thanks for your quick reply nick12ab.

I think the first step is to reprogram the 18M2 on the LCD. However I'm a bit confused as what to enter, what parts of the code you provided do I need to insert? The LCD display is showing two rows of black boxes, this is with the contrast on the pot fully turned.

I have attached photos. The project is part of a bigger project using an LCD display as an output to display RPM and a set speed condition of a motor using an IR sensor (Overspeed/Underspeed).

In the photograph of my breadboard you will notice the power rails are opposite, this is due to the wrong size PSU ordered, and no money to buy a new one.

Thanks a lot

Steven

 

[si_90]

Another photo of the LCD PCB

 

[Technical]

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.

 

[nick12ab]

The connectors on the LCD look a bit lacking in solder. Are they all making good contact? Also the serial connection to the LCD is connected to a darlington output - it must be connected directly to a PICAXE output pin.

I think the first step is to reprogram the 18M2 on the LCD. However I'm a bit confused as what to enter, what parts of the code you provided do I need to insert? The LCD display is showing two rows of black boxes, this is with the contrast on the pot fully turned.

The entire code should be copied into a blank file, then the PICAXE on the AXE133 PCB (only) should be programmed with it.

I have attached photos. The project is part of a bigger project using an LCD display as an output to display RPM and a set speed condition of a motor using an IR sensor (Overspeed/Underspeed).

Please provide close-up photos of the CHI030B. Just off-camera to the right in your last photograph there is a jumper link (or zero-ohm resistor) which needs to be in place for the board to work from a single supply.

In the photograph of my breadboard you will notice the power rails are opposite, this is due to the wrong size PSU ordered, and no money to buy a new one.

You could rotate the breadboard 180 degrees so that + and - correspond to the correct colours, your current approach is bound to blow something up eventually.

 

[si_90]

Hi Folks,
I got it working massive thanks for your help
I first reprogrammed the 18M2 LCD with the firmware code provided.
I added a bit of extra solder to the connections just to be sure and checked with the meter to ensure contact.
I didn't even think of adding jumper leads to share the connection with V2 on the project board, its worked fine with inputs and outputs before without adding the secondary jumper leads.
But done that and that seems to have solved the problem ! I connected the serial from the LCD directly to the picaxe pin b.2 before the darlington chip and it worked fine

Thanks again guys.

 

[nick12ab]

I didn't even think of adding jumper leads to share the connection with V2 on the project board, its worked fine with inputs and outputs before without adding the secondary jumper leads.

The link is normally pre-fitted to the board, so you'll only need to do this if the link has been removed at some point.