Cascading MAX7219 Drivers
The MAX7219 is an SPI LED driver that controls one 8×8 LED matrix. By connecting the DOUT pin of one MAX7219 to the DIN of the next, you can chain up to 8 modules with only 3 wires from the microcontroller (CLK, DIN, CS). The MD_MAX72XX library treats the chain as a single wide display buffer, and MD_Parola adds a high-level API for scrolling text, zone splits, and text effects.
For a scoreboard, we split the 32-column display into two zones: left zone shows Team A score, right zone shows Team B score. Two buttons increment each score.
Components
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Wiring
| LED Matrix Chain | Arduino Mega Pin |
|---|---|
| DIN | MOSI (Pin 51) |
| CLK | SCK (Pin 52) |
| CS | Pin 10 |
| VCC | 5V |
| GND | GND |
Button A (Team A +1) → Pin 2 with 10kΩ pull-down.
Button B (Team B +1) → Pin 3 with 10kΩ pull-down.
Button Reset → Pin 4 with 10kΩ pull-down.
