I am trying to get my led matrix to run off the 7219, but wierd crap is happening.
a few ideas:
- make sure you have a ground return connection between the Arduino and the 7219
- this is a high-current load, so is you power supply big enough? The Arduino's on-board regulator may not be adequate.
- high-current loads require good power supply bypassing: .1UF and 330UF capacitors between +5 and GND, located near the 7219 will do it.
D