yamani /zaily1 sequential circuit introduction to counter asynchronous counter - ripple ...
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YAMANI /ZAILY 1
Sequential Circuit
Introduction to Counter Asynchronous Counter - Ripple Asynchronous Down Counter Synchronous Counter – Parallel Synchronous Counter Up/Down Designing Synchronous Counter Counter with Parallel Load
YAMANI /ZAILY 2
Sequential Circuit
Contents Register Introduction
Simple register Register with parallel load
Shift Register Shift Register Serial In/Serial Out Shift Register Serial In/Parallel Out Shift Register Parallel In/Serial Out Shift Register Parallel In/ Parallel Out
Two way shift register Random Access Memory
YAMANI /ZAILY 3
Sequential Circuit: Counter
Introduction Counter is a circuit which cycle through state sequence Two types of counter
Synchronous counter (e.g. parallel) Asynchronous counter (e.g. ripple)
Ripple counter let some flip-flop output to be used as clock signal source for other flip-flop
Synchronous counter use the same clock signal for all flip-flop
YAMANI /ZAILY 4
Sequential Circuit: Counter
Asynchronous Counter (Ripple) Asynchronous Counter : flip-flop doesn’t
change condition simultaneously because it doesn’t use single clock signal
Also known as ripple counter because clock signal input as ripple through counter
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Sequential Circuit: Counter
Asynchronous Counter (Ripple) Example: 2-bit ripple counter Output from one flip-flop is connected to clock input for the
next flip-flop MSB
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Sequential Circuit: Counter
Asynchronous Counter (Ripple) Example: 3-bit ripple counter
YAMANI /ZAILY 7
Sequential Circuit: Counter
Asynchronous Counter (Ripple) Example: 4-bit ripple counter (negative edge triggered)
YAMANI /ZAILY 8
Sequential Circuit: Counter
Asynchronous Down Counter The previous example is up asynchronous counter Down asynchronous counter count from large to zero and
repeat Example: 3-bit binary down counter
YAMANI /ZAILY 9
Sequential Circuit: Counter
Asynchronous Down Counter Example: 3-bit binary down counter (MOD 8)
YAMANI /ZAILY 10
Sequential Circuit: Counter
Synchronous Counter (Parallel) Synchronous counter: flip-flop with the same synchronous
clock signal We can build synchronous counter using process to design
sequential circuit Example: 2-bit synchronous binary counter (using T flip-
flop or JK)
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Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: 2-bit synchronous binary counter (using T flip-
flop or JK) cont….
YAMANI /ZAILY 12
Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: 2-bit synchronous binary counter (using T flip-
flop or JK) cont….
YAMANI /ZAILY 13
Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: 2-bit synchronous binary counter (using T flip-
flop or JK) cont….
YAMANI /ZAILY 14
Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: 2-bit synchronous binary counter (using T flip-
flop or JK) cont….
YAMANI /ZAILY 15
Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: BCD Synchronous Counter
YAMANI /ZAILY 16
Sequential Circuit: Counter
Synchronous Counter (Parallel) Example: BCD Synchronous Counter
YAMANI /ZAILY 17
Sequential Circuit: Counter
Up/Down Synchronous Counter Up/Down Synchronous Counter: two way counter which
able to count up or down Up/Down control input line which determine the counter
Up/Down = 1 (count up) Up/Down = 0 (count down)
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Sequential Circuit: Counter
Up/Down Synchronous Counter Example: 3-bit Up/Down Synchronous Counter
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Sequential Circuit: Counter
Up/Down Synchronous Counter Example: 3-bit Up/Down Synchronous Counter (cont)
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Sequential Circuit: Counter
Designing Synchronous Counter See sequential logic lecture notes Example: 3-bit Gray Code Counter (using JK flip-flop)
YAMANI /ZAILY 21
Sequential Circuit: Counter
Designing Synchronous Counter 3-bit Gray Code Counter: flip-flop input
YAMANI /ZAILY 22
Sequential Circuit: Counter
Designing Synchronous Counter 3-bit Gray Code Counter: logic diagram
YAMANI /ZAILY 23
Sequential Circuit: Counter
Counter with Parallel Load Counter with Parallel Load able to
Count at different condition Count in different sequence For increment/decrement function
YAMANI /ZAILY 24
Sequential Circuit: Counter
Counter with Parallel Load Different method to get MOD-6 counter
YAMANI /ZAILY 25
Sequential Circuit: Counter
Counter with Parallel Load Counter with 4-bit parallel
load
YAMANI /ZAILY 26
Sequential Logic
Contents Register Introduction
Simple register Register with parallel load
Shift Register Shift Register Serial In/Serial Out Shift Register Serial In/Parallel Out Shift Register Parallel In/Serial Out Shift Register Parallel In/ Parallel Out
Two way shift register Random Access Memory