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Topic: 16x16 LED Matrix using MAX7219 for Arduino (Read 18702 times) previous topic - next topic

sgharbi11

hi MARCO!

thank you for the sketch and the PAROLA libraries. if i decided to build a 80*16 do matrix using your sketch. It necessary  any change in the parola code. if yes what is this change?

Can you help me?  

marco_c

I am assuming that you want to create letters 16 LEDs high scrolling across the display.

The majority of changes will need to be in the MD_MAX72XX library, and the extent of the changes is not trivial. If you are not experienced I would not recommend this.

0. Above all else you will need to be clear how the hardware will be configured as you will need to take this into account in the way that the data is sent to the MAX7219 chips.
1. The font definition will need to change in order to map to 16 pixels high instead of 8. All associated code will need to change for the new font and hardware configuration.
2. All definitions on the display buffers that use uint8_t will need to change to uint16_t. All code processing buffers (shifts, transformations, SPI comms, buffer management) will need to be inspected and adapted.
3. Testing, testing, testing ...

There should be few, if any, changes needed for the MD_Parola library as these are hardware independent, using the MD_MAX72xx library to take care of those details.
Arduino Libraries https://github.com/MajicDesigns?tab=Repositories
Parola for Arduino https://github.com/MajicDesigns/Parola
Arduino++ blog https://arduinoplusplus.wordpress.com

sgharbi11

hi marco!
that's way i ask you, i am not an excellent experienced, i have the font map to 16 pixels, but i don't know how change the program to command 4 matrix at the same time. have you an example of the parola libraries the command 16*16 matrix. Please give me a hand.

marco_c

#18
Jan 21, 2015, 01:53 am Last Edit: Jan 21, 2015, 01:54 am by marco_c
No example is available unless someone else can provide it.

Are you trying to do 16x16 or 16x80 (earlier post)?

I agree with all the others - your hardware is non-standard and this is a school assignment - does that mean that you should be doing this yourself?
Arduino Libraries https://github.com/MajicDesigns?tab=Repositories
Parola for Arduino https://github.com/MajicDesigns/Parola
Arduino++ blog https://arduinoplusplus.wordpress.com

sgharbi11

Quote
Are you trying to do 16x16 or 16x80 (earlier post)?
i want to build a 16*80 but to simplify i write 16*16 it was the same code to command 16*16 dot matrix than 16*80 expect changing the MaxInUse or no?
Quote
does that mean that you should be doing this yourself?
for this I confess I'm doing it for school and i will represent it next month. Please help me this is the truth.

racemaniac

i want to build a 16*80 but to simplify i write 16*16 it was the same code to command 16*16 dot matrix than 16*80 expect changing the MaxInUse or no? for this I confess I'm doing it for school and i will represent it next month. Please help me this is the truth.

Isn't it then kind of the goal to learn how to do it yourself rather than trying to find a library that does it all for you? May i ask if you recently got this assignment and don't have much time to complete it? if you're new to this all, getting it to work in under a month is quite challenging.

sgharbi11

in addition, i am new in programming and i have not mush experience in this sector. That is why i ask for help.

racemaniac

And what exactly is your assignment? Does it require full scrolling text? or could you start out just displaying static text (but completely programmed by yourself), which would already be a bit simpler :).
If you would start now learning how to control the max 7219 without using libraries (which really isn't that hard), you could go a long way in a month, maybe even getting up to full scrolling text. But it will take quite some work :).

sgharbi11

Quote
And what exactly is your assignment?
I must prepare a code that permit to scrolling a text so, i based on the Parola libraries but i can't convert it to work with 16 * 80 dot matrix so that i ask the help from Marco and each other know how convert it.

marco_c

Getting someone else to convert a library so that the task of scrolling text becomes relatively trivial does not seem to me to be the right thing to do. I would suggest that you focus on getting 16x16 working   first with some code that you wrote (by all means copy what is is other people's libraries if you can) so that you learn. The other option is to find something less ambitious (maybe flashing LED patterns using a 595 output buffer) where you can probably do it in the time remaining.
Arduino Libraries https://github.com/MajicDesigns?tab=Repositories
Parola for Arduino https://github.com/MajicDesigns/Parola
Arduino++ blog https://arduinoplusplus.wordpress.com

Grumpy_Mike

I would suggest first rewiring the order of the matrices and rotating the bottom two, in order to make your task more straight forward.

sgharbi11

And what the solution now. Someone can't help me ?  :'(  :'(  :'(  :'(  :'(  :'(  :'(  :'(  :'(  :'(

Paul__B

And what the solution now. Someone can't help me?
I think that Mike is suggesting that it is up to you to do the work.  If you cannot locate a library to do what you want, then you are going to have to write the code.  That's the "name of the game" - unless someone else has a particular interest in the problem, or you propose to pay them (there is a separate section in these fora for just that), then it is your project.  :smiley-lol:

Do note my previous comment.  There is no insurmountable problem with the "folded" modules as you have them - but you have to write code to deal with it.  Since you want an expanded font as well, you have two reasons for "rolling your own".

Grumpy_Mike

Quote
There is no insurmountable problem with the "folded" modules as you have them -
That is true, but I am a great believer in making things easy for yourself and having them wires like you do just makes the software more complex than it could be. So I would wire it up so that you have them in this order
1  2
3  4

Then work on a font definition for say just one character. Then work on the software to transfer that one character into your multiplexing chips.

Only when that is working start to think about scrolling, at first just scrolling the one character off the display and then expand it to the next one scrolling onto the display.

The secret of any project is to make little steps and test. That way you always know what part of the code is going wrong as it is normally the code you have just written.

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