Nano & MAX7219 dot matrix

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

Here we have a working example of how to drive a 4 digit MAX7219 matrix
using Arduino Nano and using the EEprom as a character ROM
By running the Load_eeprom program the characters are loaded into the EEprom
then the main program is loaded
Also note the use of a two dimensional array to hold the characters

Regards Paul

Duval JP · Joined: 22 Jun 2004 Posts: 1161 Location: France

Nice works Paul,

I didn't know the max7219 I have seen a lot of possibilities on the web.

would you please add a picture of the results ?

JP
Wink

EDC · Joined: 26 Mar 2014 Posts: 971

Paul`s first code was for HT16K32 <- those are for SPI
For I2C HT16K33 also exitst. Both can handle two 8x8 matrixs by one chip Very Happy

Max7219 can only drive one 8x8matrix but is easy to buy and cheap so ..I code something like this.
Video don`t show best future of this code. Every character is like TrueType and I can then vertically scroll only one digit/char.
Look that first "One" in 16:59 dont move if time is change into 17:00
To show this better I buy another two led matrix and in next video also seconds will be displayed.

https://www.youtube.com/watch?v=rBkRzcZ-wfI

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

Nice work EDC.
I could not find much on the MAX7219 on the forum
when I searched, have you posted the code?
I had a need for a cheap digital display with more than 4 digits
so I worked with my previous code and also wanted to show
the use of multidimensional arrays by getting some practice using them.

I have two 64 x 32 displays on order they use a HUB08 protocol

I am very much trying to make the code I write modular
so that I can cut and paste and use include to build projects
this also means less experienced Bascom users can use what
is done by me.
I have still have much to learn as I have no formal training
so being shown how to do it more efficiently is always welcome.

Regards Paul

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

thanks for sharing Paul.

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

Now a program that asks for how many characters in your display
and sets the variable.
This is sent to a prompt on the terminal screen of your computer
after this you can type a message then hit enter and it will be
displayed on the dot matrix display.

Notes
You need to run the EEprom program first to load the fonts
Set the terminal to 9600 baud

This can not be used with the free version
but if you comment out the marked section
and set the Numdis variable in the code it can be.

Regards Paul

EDC · Joined: 26 Mar 2014 Posts: 971

I have hope that You not angry for me Paul that Im post my routines in another Forum section.
My Intention was to show my routines but also not close them only to arduino forum Very Happy

I want show them to improve by someone Very Happy

Paulvk · Joined: 28 Jul 2006 Posts: 1257 Location: SYDNEY

No not at all as I said I have much to learn
There is always more than one way to do something
If we share what we do we make each other richer in knowledge
and those like me that are self taught can learn how to use Bascom.
The other good thing about posting code to the forum is that
if something goes wrong with our computers we do not loose what we have done.

Regards Paul

aphawk · Joined: 23 Jan 2010 Posts: 168 Location: Brazil

I have made one project with Arduino using two Max7219 to make one spectrum analyzer some years ago.

I don't showed any letter, but use them to show the relative audio spectrum for 10 bands. Is a very nice IC, with fast response and communication !

The project is here with Bascom code too ( sorry, is in Portuguese ... ) :

http://www.clubedohardware.com.br/forums/topic/937085-projetos-com-avr-design-programa%C3%A7%C3%A3o-em-basic-e-assembly/?page=2#comment-5672339

Paulo