What is the full meaning of BCD?

Answer 1

BCD is binary coded decimal but unlike normal binary, the maximum number per byte is 99 instead of 255. It makes its decimal value easy to read by humans but is less efficient because of the number limits as four bits are consumed by each digit. Binary itself is easier to read if you want hexadecimal instead For numbers 0 to 9 the bit pattern is the same as binary but different from 10 onwards as shown below:

Decimal, Hex, BCD, normal Binary

000, 00, %00000000, %00000000

001, 01, %00000001, %00000001

002, 02, %00000010, %00000010

003, 03, %00000011, %00000011

004, 04, %00000100, %00000100

.....

009, 09, %00001001, %00001001

010, 0A, %00010000, %00001010

011, 0B, %00010001, %00001011

.....

015, 0F, %00010101, %00001111

016, 10, %00010110, %00010000

017, 11, %00010111, %00010001

.....

099, 63, %10011001, %01100011

.....

255, FF, not do-able with 1 byte, %11111111