MAX7219 with Arduino UNO - LED control doesn't work
OMG, the only problem was a typo in LedController initialisation! I used LedControl lc=LedControl(12,11,10,4); instead for LedControl lc=LedControl(11,12,10,4);. It seems the library has no error detection if passed data pin isn't really a data pin. Now everything works fine.