^^Codice BCD Binary Coded Decimal.

BCD Binary Coded Decimal  is just what it says it is.

Here the decimal digits 0-9 are coded into binary.

For each digit we need 4bits: 0000  0001  ...  1001;

the remaining 4-bit numbers are notused.

137₁₀   =   0001 0011 0111  _BCD

This is not the same as Binary!  looks like binary but ...

1. BCD provides ease of interfacing for digital displays e.g. 7segment displays.
2. BCD is wasteful of bits.
3. The conversion between BCD and binary iscomplicated. Thus most arithmetic operations are done with binary rather than other representations. (However it is possible to implement arithmetic in BCD but with a carry between thecolumns)

Per codificare 1 cifra decimale si usano 4 bit, la cui combinazione fornisce 2⁴=16 combinazioni.