WK223
www.wineyard.in
DIGITAL CODE CONVERTERS BCD TO
GREY/EXCESS-3/7-SEGMENT
In
computing
and
electronic
systems, binary-coded
decimal BCD
(sometimes called natural binary-coded decimal NBCD )is an encoding for decimal
numbers in which each digit is represented by its own binary sequence. Its main virtue is
that it allows easy conversion to decimal digits for printing or display and faster decimal
calculations. Its drawbacks are the increased complexity of circuits needed to
implement
mathematical
operations
and
a
relatively
inefficient
encoding—it
occupies more space than a pure binary representation.
In BCD, a digit is usually represented by four bits which, in general,
represent the values/digits/characters 0¹. Other bit combinations are sometimes used
for a sign or other indications. Although BCD is not as widely used as it once was,
decimal fixed-point and floating-point are still important and continue to be used in
financial, Commercial,
and
industrial computing.
Modern decimal floating-point
representations use base-10 exponents, but not BCD encodings. Current hardware
implementations, however, convert the compressed decimal encodings to BCD internally
before carrying out computations. Software implementations use BCD or some other 10
base, depending on the operation.
This Binary coded decimal (BCD) can be converted in to GREY CODE,
EXCESS -3 codes, or even in the SEVEN SEGMENT DISPLAY can be displayed on
16X2 LCD. This code conversion is simple example for Data encryption procedure. A
truth table is written for Grey, EX-3 and 7- segment . Logic equations are derived from
the truth table. .
Hyderabad: Tarakarama Estates, 2nd Left Lane Opp RS Brothers, Ameerpet, Hyderabad – 500073
www.WineYard.in Ph: 040 – 6464 6363, 6625 6695, 888 5555 212
ABSTRACT:
WK223
www.wineyard.in
According to the simplified logic equations, logic circuit is built using basic
logic
gates.
Three Toggle switches are connected at the input side to give BCD
input.5mm .LEDs are connected at the output side for visual identification of the Exc-3,
This project uses regulated 5V, 750 mA power supply.7805 three terminal voltage
regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify
the ac out put of secondary of 230/18V step down transformer.
Hyderabad: Tarakarama Estates, 2nd Left Lane Opp RS Brothers, Ameerpet, Hyderabad – 500073
www.WineYard.in Ph: 040 – 6464 6363, 6625 6695, 888 5555 212
Grey ,7-segment display as Output.
WK223
www.wineyard.in
POWER
SUPPLY
16X2 LCD
DISPLAY
4X4
KEY PAD
8
9
S
5
2
SWITCH 1
SWITCH 2
SWITCH 3
Crystal
Reset
Step
down
T/F
Bridge
Rectifier
Filter
Circuit
Regulator
Power supply to all sections
Hyderabad: Tarakarama Estates, 2nd Left Lane Opp RS Brothers, Ameerpet, Hyderabad – 500073
www.WineYard.in Ph: 040 – 6464 6363, 6625 6695, 888 5555 212
BLOCK DIAGRAM: