hello.
I have 12 max 7219 connected to an arduino, when I connect all, the signal in ports of arduino is degraded in speed because the capacity of the inputs of all max 7219-
then the matrix starts ok and after 10 seconds the matrix crash, leds stay on, leds stay off, leds bright be increased.... etc.
you need do this circuit to drive the inputs (of max7219) capacity.
other solution that I tried is change crystal of arduino, I put a 2.9mhz xtal and the result is good, but not perfect.
good luck with your proyect.
Ariel.
Argentina.
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Bob.
OK, took me a while to figure out what you are on about.
Yes, this is an appropriate way to buffer the control pins of a number of MAX7219s. You can also use a 74HC14, or a 74HCT14 if driving with an ESP8266.
In fact, this is more of a problem if there is significant wiring distance between the modules.