yumology:
Hello,
I am trying to put together a circuit using my arduino mega 1280, a max7219 LED driver and a 8x8 LED matrix.I have torn down my circuit and rebuilt it. I have swapped every part and wire also. For some reason, my LED matrix lights up ALL the led's all the time. Can someone help me understand what I'm doing wrong? Even if I set the intensity to 1 the brightness doesn't change. Even if I indicate that only 1 LED should turn on, they still turn on. Even if I set lc.shutdown(0,true) they all stay on.
From the symptoms it sounds like you're putting the 7219 into "test" mode. Normally you'd have to do that deliberately but it could happen if you only ever put '1's on the data line (the test register is register 0x0f and you put '1's into it...)