Problem occurred when Cascading 8 MAX7219 8x8

Equipment Arduino Nano 328G MAX7219 8x8

A summary of my project

1) Cascading 8 MAX7219 module 8x8 into a row 2) MaxMatrix library to control my LED display 3) Display "0123456789" using sprite

By doing so my display was distorted, sometimes only the last 2 modules are lighted up. It is powered solely by the NANO, and I believe it is only able to provide 0.5A to the LED module. Is this the reason why I get distorted display?

|500x353

Probably. Read this https://arduinoplusplus.wordpress.com/2015/09/12/max7219-and-led-matrix-power-requirements/

haruna_ono: |500x353

By doing so my display was distorted, sometimes only the last 2 modules are lighted up. It is powered solely by the NANO, and I believe it is only able to provide 0.5A to the LED module. Is this the reason why I get distorted display?

Probably not.

The Nano will provide whatever the USB port is providing to it. That might be limited to 500 mA, but probably is not. The displays will work - as will the Nano - down to a lower voltage.

From your photo, the "last two" displays are the first two in the chain - which makes sense if it is scrolling from right to left. This problem is commonly reported, presumed due to excess loading of all the wiring and chips in parallel on the clock line - and perhaps the latch line. The data line is not involved as it is chained. If the library uses hardware SPI, this may simply be too much capacitance. It would be logical to supply buffers (such as pairs of gates in a 74HC14) to different sections of the chain.

Using software shiftOut() with slower clocking might be an alternative.

Those crude eBay display modules are ugly - I know, I have at least as many of them myself. The proper version now sold (at the same price) are much better and you use no wire between, so they would most likely be more reliable (but they are oriented 90˚ differently). Of course, Marco is the expert and knows all this. :grinning: |500x500 |500x471


Now when I say "Probably not", it is because in displaying numbers, you are using nowhere near the whole 64 LEDs per display.

And while the cruder modules each include a 10 µF capacitor to help with the impulse currents, the better (designed) ones do not, so when chaining them you should perhaps add a 47 µF capacitor across the supply connections every three modules or so.