My car has a digital speedometer and it has stopped working !!?

[WiSHiWaSSuperman]

My car has a digital speedometer and it has just stopped working, it still lights up and all the other instruments work, the speed and miles just don’t show up…Please can somebody help me; I have already checked the fuses nothing wrong with them. What else could it be? And can it pass a smog check without a proper working speedometer?