Digital electronics- BCD & Decoder

Digital electronics- BCD & Decoder

1. Welcome to our presentation

2. BCD & Decimal Decoder

3. Md.Aklasur Rahman Robin 162-15-7708 Md. Rakibul Hasan 162-15-7735 Pritam Chandra Shil 162-15-7882 Md. Ariful Islam 162-15-7885 Our team members

4. BCD

5. About BCD In computing and electronic systems, binary-coded decimal (BCD) is a class of binary encodings of decimal numbers where each decimal digit is represented by a fixed number of bits, usually four or eight. Special bit patterns are sometimes used for a sign or for other indications

6. Binary coded decimal (BCD) is a system of writing numerals that assigns a four-digit binary code to each digit 0 through 9 in a decimal (base-10) numeral.The four-bit BCD code for any particular single base-10 digit us is its representation in binary notation , as follows : 0=0000, 1=0001,2=0010.

7. BCD Sum

8. BCD Adder circuit

9. BCD in electronics B CD is very common in electronic systems where a numeric value is to be displayed, especially in systems consisting solely of digital logic, and not containing a microprocessor. By employing BCD, the manipulation of numerical data for display can be greatly simplified by treating each digit as a separate single sub-circuit. This matches much more closely the physical reality of display hardware—a designer might choose to use a series of separate identical seven-segment displays to build a metering circuit

10. Decimal Decoder

11. Rules of Decimal Decoder Digital information represented in some binary form must be converted into some alternate binary form. n to - -line Decoder. Only one of the outputs lines responds, with a logic-1, to a given input combination of values on its n-input  

12. 2 to 4 binary Decoder

13. 2 to 4 binary decoder diagram

14. BCD to Decimal Decoder BCD Decoder have four inputs and 10 out puts. The four bit BCD input is decoder to activate one of the ten outputs. Its accepts four active high BCD inputes ans provides 10 independent active low outputs.

15. Other type of Decoders Function-specific decoders with less than outputs exist. Example: Decoder with 4 inputs and 10 outputs in which a single responding output line corresponds to a combination of the 8421 code. Example : Four input , seven output decoder that accepts the 4 bit of the 8421 code and is used to drive a seven-segment display .  

16. Logic Design Using Decoders An n-To- enerator. By using or-gates in conjuncation with an n-To- line decoder ,realizations of Boolean funcation are possible. Do not correspond to minimal sum-of-products. Are simple to Product. Particularly convenient when serveral functions of the same variable have to be realized.  

17. Decimal Adders Weighted coding scheme or BCD code Decimal Digit BCD 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0110 7 0111 8 1000 9 1001 . Forbidden codes: 1010,1011,1100,1101,1110,1111

18. BCD to Decimal Decoder BCD to decimal decoder accept a binary coded decimal and activate one of ten possible decimale digit indications. IC: 74hc42 QUESTION: Assume the inputs of the 74hc42 decoder are the sequence 0101,0110,0011 and 0010. Answer: All lines are HIGH except for one active out active output ,which id LOW. The active outputs are 5,6,3 & 2 in that oder . BCD/DEC