05-08-2013 01:34 PM
I am new to multisim, and indeed to digital theory in general. I am trying to wrap my head around shift registers, and i'm hoping someone can help me out.
Attached is a circuit with a 74164 driving 8 LEDs. I've bridged A & B high, so it's enabled and has a constant HIGH being fed into the register. The switch acts as a clock pulse to slow things right down. CLR is grounded.
I would have thought that when you simulate a clock pulse by toggling the switch, the output LEDs would start low, and start shifting the HIGH signal down the outputs with each clock pulse. But no, all the LEDs stay low.
Can someone educate me on what i'm sure is a fairly simple problem? Is my circuit wrong, or my reasoning?
Solved! Go to Solution.
05-08-2013 03:35 PM
The clear is active low. Tie it high.
05-09-2013 05:04 AM
I knew it had to be something simple. I tried a lot of combination, but i obviously missed that one.
Thanks for the help.