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Topic: Scrolling text on LED matrices using SPI and arduino Mega2560 (Read 8 times) previous topic - next topic

CrossRoads

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Aaron_dyer

Thanks for clearing up the sequence layout.:you have been so helpful.....I'm a junior engineer with a good yr. Arduino time......just wanting this to be right....ill upload in the morning once I do the caps better....need to find some 104's

CrossRoads

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Aaron_dyer

ok heres the latest...

I placed all the caps  some 10 uF polarized electrolytic  and some 0.1 uF (104) ceramic caps   on each of the max7219s  Vcc line....

I uploaded the code you fixed up for me.....

before, the matrices would just stay on fully 3 of 4 that is.....

now.....they do go out...I'm sure its due to the register clear you mentioned....

However,

I open the serial monitor with the USB stil plugged into the mega 2560 and type hello...

theres nothing on the matrices....but when I press enter after typing hello, the LCD resets.....

I made sure the layout sequence of the matrices was correct right...and Ohmed for a good 30 minutes that all the paralleling is measuring continuity....


Is there anyway that we can manipulate the code (without changing any wiring) to just have it scroll a string?   ---> no serial monitor...

Aaron_dyer

Ok check out the forum titled "MAX7219 in daisy chain. How many decop capacitors I need" it should be fairly newly updated, and in there is what I did.....I did end up cascading them and its working for the most part but the scrolling isn't going across one matrix to the next, it just scrolls the same letter on each matrix individually...

and the letters are backwards....I tried to swap the wiring on just one matrix to see what that would do and it made it erattic...


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