Fun With Shift RegistersA tutorial to help you understand how a shift register works.
Step 4: Clock Button Step 8 of 12
Now, connect the CLR pin of the shift register to the 5v rail. This will keep the shift register from clearing all of the bits that we shift into it.
To wire up the clock pin, connect one lead of the switch to the CLK pin. The other lead of the switch is then connected to the 5v rail. Next, connect a 10K resistor from the CLK pin of the shift register to the ground rail. This will make the defualt value of the clock pin "0" or low. When the switch is pressed, it will make the clock pin high, or "1".