Digital Techniques and Microprocessor Notes

OR operation represents addition, AND operation represents multiplication.  NOR is opposite of OR operation. it is NOT OR that is complement of OR operation.  similarly NAND operation is opposite of AND operation. it is NOT AND that is complement of AND operation.  EXOR is exclusive OR. it produces low output for similar input and high output for dissimilar input.  likewise EXNOR is exclusive NOR gate produces high output for similar input and low output for dissimilar inputs. 

let's start new point ! The logic gates... logic gates perform basic logical operation and they are basic building blocks of digital integrated circuits. logical gates are used in microprocessor, micro controller and in embedded system applications. There are three types of gates, basic, universal and special . let's see one by one !!!! NOT is a basic logic gate also called as inverter. It is single input and single output gate. it perform complement operation on data.

Here we learn how to convert binary numbers into BCD and BCD numbers into binary numbers.  Here we completed first topic of digital technique. 

Basically gray codes are used to represent K-MAP. here we learn how to convert gray codes.  1. gray to binary conversion - B3=G3 ,                                                  B2= B3+G2,                                                 B1=B2+G1,                                                  B0=B1+G0. 2. Binary to gray conversion - G3=B3,                                                  G2=B3+B2,                   ...

Here we learn excess-3 code. Excess-3 code are obtained by adding 3 into given BCD number . In this post we learn how to convert BCD number to excess-3 . it is very simple you have to add 3 into given BCD number . and second is how to convert excess-3 code into BCD. we have to subtract 3 from given excess-3 number. 

BCD arithmetic has two operations. 1) Addition 2) subtraction  BCD Addition is same as binary addition but if result is invalid BCD number, then Add 0110 i.e. 6 into the result to correct it. BCD Subtraction is also same as binary subtraction but if result is invalid BCD number then subtract 0110 i.e. 6 from the result to get correct answer. 

conversion of decimal to BCD is just checking the number is valid BCD or not? and write the binary equivalent of single digit by putting space between two numbers . here space between two converted digits is important. conversion of BCD to decimal is also easy. just write decimal equivalent of given binary number and remove space and write final number.  

The binary multiplication and binary division are same as decimal number system. Now we are discussing here about codes. They are used to give instructions to computer.  here we are discussing digital codes lets see one by one. 1. BCD - it is binary coded decimal . BCD codes are heavily used in IBM processors and database.  Binary-coded Decimal or BCD  is a way of representing a decimal number as a string of bits suitable for  use  in electronic systems. Rather than converting the whole number into binary,  BCD  splits the number up into its digits and converts each digit to 4-bit binary.   2. Gray codes-  Today,  Gray codes  are widely  used to  facilitate error correction in digital communications such as digital terrestrial television and some cable TV systems. Gray codes are used in representation of K-MAP.  3.ASCII codes-  American Standard  Code  For Information Interc...