I get a +5V signal coming out of my USBIO and it's going into the clock pin of the decade counter but it wont step, only the first LED stays lit. Must it go through a 555 timer to get a square wave, can this be simulated in software?
My general question is this: is it possible to step a decade counter from the computer?
When I try your link, it is dead.
Draw a diagram of what you have done so far.
If you are using a digital output from some I/O module, to dive your counter, yes it should be possible.
No you dont need a 555 to give a square wave, but it depend on what comes out of your USB I/O module.