picaxe to lcd displays

peter howarth

New Member
reading other peoples threads for hassles getting picaxes to work with common lcds, i note that back in june 1,2008, member westaust55 moderator, wrote the following:

"The picaxe manual has the wrong connections for the data pins ,( they are back to front ).. This has been raised by others in the past.."

also member DLP1 commented on problems with the picaxe manual , same date june 1 ,2008..

Well i rest my case, I am not the only picaxe learner who is having problems with the picaxe documentation from rev ed, that has turned out to be incorrect..

Whigh begs the obvious question.: what else in the whole rev ed documentation is incorrect ? ! well the mind boggles doesnt it..
 

westaust55

Moderator
Peter,
You mention a statement from back in 2008.
However the manual part 3 was updated in 2010 and that error corrected.

as IWP has indicated, I suggest you stay with one thread. Rather then keep starting a new thread on the same topic over and over.
To that end, I will consider to merge some of you thread later today to retain some flow to your topic.

several folks have given code or likes to code to control an LCD.

you have been asked to provide a diagram of what you have wired and the code you are trying but I have seen neither albeit you have been advised how to upload your circuit diagram. You need to help us to help you.
 
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peter howarth

New Member
Peter,
You mention a statement from back in 2008.
However the manual part 3 was updated in 2010 and that error corrected.

as IWP has indicated, I suggest you stay with one thread. Rather then keep starting a new thread on the same topic over and over.
To that end, I will consider to merge some of you thread later today to retain some flow to your topic.

several folks have given code or likes to code to control an LCD.

you have been asked to provide a diagram of what you have wired and the code you are trying but I have seen neither albeit you have been advised how to upload your circuit diagram. You need to help us to help you.
sadly this is another hurdle that for reasons unknown to me yet, as to why I am not able to upload any diagrams or photos, just not working for me at the moment, and so I am well and truly stuck, hence why I have provided my email address, despite such scam problems that may arise from doing so..i shall look at other tutorial avenues for interfacing picaxes to lcds such as the new book from the author of hackett..I am using a brand new hewlett packard laptop less than 2 months old, and so this equipment age should not be the issue..I also find it very disturbing that revolution education hasnt responded to my requests to my technical questions and problems with interfacing to common lcd displays, when , as I have pointed out , that other people have indicated issues with, and because of incorrect documentation from revolution education themselves, the very organisation that has invented the picaxe platform..And so the picaxe forum has chosen to treat me as an escape goat just because of the above , and just because the uploading of diagrams and photos hasnt worked for me as yet , for reasons unknown.. I shall order the new book from the author of hackett and try its tutorial , hopefully I can gain some ground there.. What rev ed is doing with their email address I am not sure, but at least in the past >: pre covid19, I was able to email thru to them photos and diagrams without any problems whatsoever, unlike the mysterious problems that the forum upload path that I am experiencing at the moment..
 

tmfkam

Senior Member
Ron Hackett's "PicAxe microcontroller projects for the evil genius" is the book I would recommend. He wrote a number of articles for Nuts and Volts magazine around 2009 - 2011(PicAxe Primer I think) and if you have access to those they are a superb tutorial in almost all things PicAxe.IMG_20210320_090441.jpgIMG_20210320_090459.jpgIMG_20210320_090755.jpg

It appears that if the picture size/dimensions are above a certain limit, they can't be attached. I had to reduce the above to 1296 x 972 (or near to 500kb) to get them to attach to my message.
 
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captnemo

New Member
I understand how frustrating it can be trying to get something to work.
Attached is a picaxe program that will put text in the top line and variable data in the second line of a 16 character, 2 line. parallel display.
Its composed by splicing several snippets together, that I had gotten from the forum. I found the best thing to do is to look at every command in the
program, then consult the manual as to how it is used. I believe you can go to the Nut's and Volts website and look up various articles.
You learn as you go along. For instance today, I placed text in memory locations using the data command and then tried to replace that text by writing over it farther down in the program and the editor would not let me do it.
By the way. This is a mystery to me. I too was having problems with an LCD display and could not get my program to work. I cycled the power to the LCD and the Picaxe and bingo the LCD displayed the text. That told me my program was fine, after wasting several hours fooling with the program.
Also, it important that you get the contrast adjusted properly (potentiometer) otherwise you won't see anything on the display.
 

Attachments

lbenson

Senior Member
For instance today, I placed text in memory locations using the data command and then tried to replace that text by writing over it farther down in the program and the editor would not let me do it.
Can you provide an example of what you were trying to do that didn't work as you intended? On the face of it, it sounds doable--any value placed in the EEProm with DATA can be moved somewhere else in RAM--or EEPROM or scratchpad (for X2s). And data in the eeprom can be replaced with the WRITE command.

Depending on the source or destination, data can be retrieved/written with READ/WRITE, PEEK/POKE, GET/PUT, @bptr, @ptr.
 

peter howarth

New Member
Ron Hackett's "PicAxe microcontroller projects for the evil genius" is the book I would recommend. He wrote a number of articles for Nuts and Volts magazine around 2009 - 2011(PicAxe Primer I think) and if you have access to those they are a superb tutorial in almost all things PicAxe.View attachment 24555View attachment 24556View attachment 24557

It appears that if the picture size/dimensions are above a certain limit, they can't be attached. I had to reduce the above to 1296 x 972 (or near to 500kb) to get them to attach to my message.
Thankyou, I'm not sure what your first name is, however I was trying to upload a photo yesterday and the server said my photo was too large to process to the forum hence the frustrations of trying to explain better the probs at my end..Is the nuts and volts magazine an english/uk publication as I havent seen these in any australian newsagents ..That aside I shall invest in the book as you have shown, excellent, I shall let you know how I go with it
 

peter howarth

New Member
Hello Peter,
Yes your test photo upload has worked and we can see the plants
Thankyou for that, next step to do is work out why a photo that I was trying to upload yesterday spat back at me because the forum server said it was too large, frustrating to say the least.. How do i reduce the photo file size to fit a smaller marble thru the same size funnel hole"
 

westaust55

Moderator
Looking in the forum help: Help | PICAXE Forum

"You may attach up to 5 images, max size 1024k each. Supported types are jpg and png."

One way to reduce the file size is to use MSPaint - available with MS Windows.

As a guide, if your file is say 2 MB then you need to halve the file size.
In that case use a figure of 70% (0.7 x 0.7 = 0.49 gives 49% of the original pixels and roughly have the file size.
As a formula: scale factor = 1 / squareroot(initial MB) so 1/sqrt(2) ==> 0.707

Re-size an image in MSPaint.png


When taking photos of breadboards or circuit boards, suggest you aim to get in close AND include the entire circuit and take the photos of both side in the case of circuit boards perpendicular (square-on) to the breadboard or circuit board.
Best of any other wiring is tidy and short to make it easy to follow,as that makes it easy for folks to trace the wiring/circuit and help you.
 

tmfkam

Senior Member
Is the nuts and volts magazine an english/uk publication as I havent seen these in any australian newsagents ..That aside I shall invest in the book as you have shown, excellent, I shall let you know how I go with it
Nuts and Volts is a USA publication. Given the age of the PicAxe Primer articles you may be lucky and find some in the archives?

On my Tablet I don't get any messages that the image is (was) too large. Then I do have pop-ups blocked...
 

Flenser

Senior Member
Peter,
The articles "Taming Unruly LCDs" parts 1 and 2 may not be useful to you.

These two articles are all about making stripboard circuits to connect a PICAXE chip to the LCD. They don't describe how to drive the LCD but they do include code that can be downloaded. These artlcles are now quite old and Part 1 is for connecting a PICAXE 28X1 chip to the LCD and Part 2 for connecting a PICAXE 14M chip to the LCD.

The Part 1 article referred to an earlier article "Getting Started With PICAXE MICROCONTROLLERS PART 2" from Feb 2007 which described how to drive the LCD and how to connect a PICAXE 18X chip to the LCD.

You can download the code from these articles at this link Nuts & Volts Downloads
 

tmfkam

Senior Member
Peter,
The articles "Taming Unruly LCDs" parts 1 and 2 may not be useful to you.

These two articles are all about making stripboard circuits to connect a PICAXE chip to the LCD. They don't describe how to drive the LCD but they do include code that can be downloaded. These artlcles are now quite old and Part 1 is for connecting a PICAXE 28X1 chip to the LCD and Part 2 for connecting a PICAXE 14M chip to the LCD.

The Part 1 article referred to an earlier article "Getting Started With PICAXE MICROCONTROLLERS PART 2" from Feb 2007 which described how to drive the LCD and how to connect a PICAXE 18X chip to the LCD.

You can download the code from these articles at this link Nuts & Volts Downloads
When trying to get LCDs working on a PicAxe 14M2 I actually found the articles immensely useful. The descriptions of the required command sequences to initialise the displays in 4bit and 8bit mode(s) made the code I obtained from this forum (Hippy's 14M2 code I believe) understandable and allowed me to modify it to do what I was looking for.

The book was written for later processors, though off the top of my head majors on the 28X2. The 14M2 is used as a peripheral device, including an LCD display.

For background description of the operation of these parallel LCD displays I've read nothing better.
 
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