Unsigned and Signed Binary Integers : An unsigned binary integers has no arithmetic sign. Unsigned binary numbers are therefore always positive. An example is memory address which is always a positive number. An 8 bit unsigned binary integer represents all numbers from 00(16) through FF(16).
A signed binary integer on the other hand includes both positive and negative numbers. It is represented in true from for a positive number and in twos complement from for a negative number. For example the decimal number +10 can be represented as a true form 8- bit number in a microprocessor as 00001010 or 0A. the decimal number -10 can be represented in twos complement form as 11110110 or F6.
BCD Numbers : A BCD digit consists of four bits with a value ranging from (0000)2, to (1001)2. A BCD digit greater than 9(10) can be represented as two or more BCD digits. Microprocessors store BCD numbers in two forms packed and unpacked.
ASCII : ASCII is a code that represents alphanumeric in a microcomputers memory. ASCII also represents special symbols such as # and %. It is a 7 bit code. The most significant bit is sometimes used as a parity bit. The parity bit represents the number of ones in the byte. If the number of ones is odd the parity is odd, otherwise the parity is even. Read More