D-Type Flip Flops Benchmark Companies Inc PO Box 473768 Aurora CO 80047 Lecture Overview D Flip-Flops  Asynchronous Input  Sample Flip-Flop Applications 

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Transcript D-Type Flip Flops Benchmark Companies Inc PO Box 473768 Aurora CO 80047 Lecture Overview D Flip-Flops  Asynchronous Input  Sample Flip-Flop Applications 

Slide 1

D-Type Flip Flops
Benchmark Companies Inc
PO Box 473768
Aurora CO 80047


Slide 2

Lecture Overview
D Flip-Flops
 Asynchronous Input
 Sample Flip-Flop Applications



Slide 3

Gated D-Type Latch
The D-Latch is an expanded version of an RS Flip Flop.
The symbol shown is used to represent this type of flipflop.


Slide 4

Gated D-Type Latch
It is also known as transparent latch, data latch, or
simply a gated latch


Slide 5

Gated D-Type Latch
It has a data input and an enable signal (sometimes
named clock or control).


Slide 6

D-Type Flip-Flops
The D flip-flop can be interpreted as a primitive delay
line or zero-order hold, since the data is posted at the
output one clock cycle after it arrives at the input


Slide 7

D Flip-Flop
The Data Table below illustrates the output Q(n+1) with
respect to the Data (D) clocked (CLK) into the latch.
D

Q
Q

D CLK

Q

0



0

1



1

n+1


Slide 8

D Flip-Flop
As illustrated below the clock pulse into the Flip Flop (FF)
will synchronize the output.

D

Q
Q
CLK
D
Q

D CLK

Q

0



0

1



1

n+1


Slide 9

Application of D Flip-Flops



Data Storage



Counters & State Machine Designs



Logic Synchronizing



Divide By Circuits


Slide 10

Logic Synchronizing
Synchronizing data is done by clocking all D-Type FF with
the same clock. This puts data on A,B and C at the same
time.


Slide 11

Divide By Circuit using a D Flip-Flop
The D-Type FF can be configured to divide the pulse in half
by configuring the circuit below.

SIG_IN
SIG_OUT


Slide 12

Types of D Flip-Flops
D

Q
Q

D

Positive Edge Triggered

Q

Q

Negative Edge Triggered

The trigger happens during the designed trigger edge.


Slide 13

Types of D Flip-Flops
D

Q
Q

D

Q
Q

Positive Level Triggered

Negative Level Triggered

The trigger happens during the designed trigger level


Slide 14

Types of D Flip-Flops
Asynchronous Inputs
P-SET

D

Q
Q
CLR

D Flip-Flop w/ Preset & Clear
P-SET CLR D CLK
0
1 X X
1
0 X X
0
0 X X
1
1 0 

1

1

1



Q
1
0
?
0

n+1

(preset)
(clear)
(illegal)

1

The FF can be designed with Preset (P-SET) or clear (CLR)


Slide 15

End of Lesson