Binary Coded Decimal

What is a Binary Coded Decimal?

What is Binary Coded Decimal

Binary Coded Decimal is a form of binary representation where each denary digit is converted individually into binary, rather than the whole number being converted as a large number.

Example 1 – the number 42

Normally this number would be converted directed to binary as 00101010  as 8 bit binary.

128 64 32 16 8 4 2 1
0 0 1 0 1 0 1 0

However in binary coded decimal we would convert the number 4 to binary and the number 2 to binary, then simply concatenate(combine) the 2 numbers together

Binary 4

8 4 2 1
0 1 0 0

Binary 2

8 4 2 1
0 0 1 0

 

Therefore 42 in BCD binary would be 01000010

Why use BCD?

Why use Binary Coded Decimal?

Binary coded decimal has 3 main advantages

  • It is easier for a human to read large binary numbers than if the number is in pure binary
  • It is simpler to create hardware than only counts in decimal and uses basic calculation (e.g. digital clocks, simple handheld calculators)
  • Binary coded decimal removes the problem of floating point rounding errors, which makes is very useful for handling financial transactions.

 

 

BCD Clock Demo

Binary Coded Decimal Clock Demonstration Project

The Scratch project for this clock can be found here