Arduino Driver Library for a MAX7219 driver chip using 7 segment LED displays
Pin connections
Name Arduino ESP8266/Wemos D1 MAX7219 7 Segment display
----- ------- ------- -------------------------
+5V 5V** VCC
GND GND GND
DIN D11/MOSI GPIO13 (D7) DIN
CS *D7/SS *GPIO15 (D8) CS
CLK D13/SCK GPIO14 (D5) CLK
* The CS connection is user selectable.
** From the USB 5V supplied to the Wemos D1 Mini PCB, The MAX7219 needs 5V