Apa yang dimaksud BCD atau BinaryCodedDecimal?

Binary coded decimal (BCD) is a system

of writing numerals that assigns a four-

digit binary code to each digit 0 through

9 in a decimal (base-10) numeral. The

four-bit BCD code for any particular

single base-10 digit is its representation

in binary notation, as follows:

0 = 0000

1 = 0001

2 = 0010

3 = 0011

4 = 0100

5 = 0101

6 = 0110

7 = 0111

8 = 1000

9 = 1001

Numbers larger than 9, having two or

more digits in the decimal system, are

expressed digit by digit. For example, the

BCD rendition of the base-10 number

1895 is

0001 1000 1001 0101

The binary equivalents of 1, 8, 9, and

5, always in a four-digit format, go

from left to right.

The BCD representation of a number is

not the same, in general, as its simple

binary representation. In binary form,

for example, the decimal quantity 1895

appears as

11101100111

Other bit patterns are sometimes used

in BCD format to represent special

characters relevant to a particular

system, such as sign (positive or

negative), error condition, or overflow

condition.

The BCD system offers relative ease of

conversion between machine-readable

and human-readable numerals. As

compared to the simple binary system,

however, BCD increases the circuit

complexity. The BCD system is not as

widely used today as it was a few

decades ago, although some systems

still employ BCD in financial applications.