Hi Eric Thanks for the reply.
I understand a bit.
Eric to shift the bit it needs a CLOCK, but to change the state of the current bit it needs the A & B inputs state am I right?
The 'A or B' input is used as a gating signal for the other serial input.
Let 'B' be low for example, then as the S/R is CLOCKED, whatever the state of 'A' the data pin, it dosnt get clocked into the S/R, as the low on 'B' has inhibited the data bit from being clocked in.
If now 'B' is high, whenever the S/R is CLOCKED, the state of the 'A' pin is shifted into the S/R.
I'm wondering why it needs two inputs (A & B) to change the state? One is more than enough.
It dosnt need two input to change the state, BUT one of the inputs has to be high in order the DATA on the other serial input to be CLOCKED in.Ex:A = HIGH the output will be HIGH
A = LOW the output will be LOW