|
== Barrel ShiftersLaskurit ==
== Cascade Shifters ==
== Laskurit ==
A counter is a sequential circuit that – counts. That means it proceeds through a
pre-defined sequence of states where the state of the circuit is determined by the
states of all its flip flops. As every state of the circuit can be given a number we can
say that a counter produces a sequence of numbers. A commonly used approach is
to interpret a circuits state as dual number, so if flip-flop A,B and C are all 0 the
counter’s state is 0. if A is 1, B is 0 and C is 1 the counter’s state is 101 = 5 and so
on. The most basic counters will simply increment by 1 with every clock pulse, so
after state 100 it will go to 101; the next pulse will let it switch to 110 etc. It is
possible to design counters with any needed counting sequence. Even though
asynchronous sequential circuits are not subject of this course the asynchronous
counter is presented here exceptionally to give a slight impression on how
[[Image:4 bit counter.png|center|500px]]
===Johnson-laskuri===
==Two types of counters:==
-Asynchronous/Ripple Up counters,
-Synchronous Up counters.
===Binaarilaskurit===
| 