3 To 8 Decoder Vhdl Code

3: 8 Decoder using basic logic gates Here is the code for 3: 8 Decoder using basic logic gates such as AND,NOT,OR etc.The module has one 3-bit input which is decoded as a 8-bit output.libraries to be used are specified here. For a 3: 8 decoder, total number of input lines is 3 and total number of output lines is 8. Based on the input, only one output line will be at logic high. The verilog code for 3:8 decoder with enable logic is given below. 3:8 Decoder Verilog Code. Module decoder3to8( in,out, en);input 2:0 in;input en;output 7:0 out; reg 7:0 out; always @( in or en)begin if (en) begin out=8'd0; case (in) 3'b000: out0=1'b1.

Entity decoder is port ( x : in std_logic_vector (2 down too)

Y : out std_logic_vector ( 0 down to 7 )

en : in std_logic) ;

End decoders;

Architecture behavioral of decoder is signal Y 1 : std_logic_vector (7 down to 0) ;

BeginY1 < = '0111 111' when z = ' 000 ' else

'10111111' when x = '001' else

'11011111' when x = '010' else

'11101111' when x = 011' else

'11110111' when x = '100' else

'11111011' when x = '101' else

'11111101' when x = '110' else

'11111110' when x = '111' else

'11111111' when others;

Y < = y, when en = ‘0' else '1111 1111' ;

End behavioral.

Just as Multiplexer, Decoder is also a Combinational circuit which transforms given inputs to a maximum number of outputs (maximum outputs equal to 2ⁿ and n are given inputs ).

A block diagram of decoder consists of input lines, one or more enable inputs and a maximum number of output lines.
To construct a decoder, we require to know the number of all possible output lines that totally depends on the given input.

So, if n represents given input lines then possible output lines would be 2ⁿ.
Decoder with three inputs would give 8 outputs (n=2,2³ that is 8).

Here are the steps to construct 3 to 8 decoder

Step 1. Now we know possible outputs for 3 inputs, so construct 3 to 8 decoder, having 3 input lines, a enable input and 8 output lines. In the below diagram, given input represented asI2, I1 and I0 , all possible outputs named as O_0, O_1, O_2,O_3, O_4, O_5,O_6& O₇ and a E were represented by Enable input.

With Enable input

Without Enable input

Step 2. Now, it turns to construct the truth table for 3 to 8 decoder. E input can be considered as a control input. Mean to say, If E equals to 0 then the decoder would be considered as disabled regardless of what inputs are, If E equals to 1 then the decoder would work as per inputs.

Truth table without E input

3 To 8 Decoder Vhdl

We can represent the following output as:

O₀ = I₀‘.I₁‘.I₂‘
O₁ = I₀.I₁‘.I₂‘

Vhdl Code For 3 To 8 Decoder Using Structural Modelling

Explanation:

In above diagram, there were three input lines along with their complements using Inverters. Each and every AND gate were holding four inputs from E, I1, I1 and I0 and producing 8 outputs.

3: 8 Decoder using basic logic gates Here is the code for 3: 8 Decoder using basic logic gates such as AND,NOT,OR etc.The module has one 3-bit input which is decoded as a 8-bit output.libraries to be used are specified here. For a 3: 8 decoder, total number of input lines is 3 and total number of output lines is 8. Based on the input, only one output line will be at logic high. The verilog code for 3:8 decoder with enable logic is given below. 3:8 Decoder Verilog Code. Module decoder3to8( in,out, en);input 2:0 in;input en;output 7:0 out; reg 7:0 out; always @( in or en)begin if (en) begin out=8'd0; case (in) 3'b000: out0=1'b1.

Entity decoder is port ( x : in std_logic_vector (2 down too)

Y : out std_logic_vector ( 0 down to 7 )

en : in std_logic) ;

End decoders;

Architecture behavioral of decoder is signal Y 1 : std_logic_vector (7 down to 0) ;

BeginY1 < = '0111 111' when z = ' 000 ' else

'10111111' when x = '001' else

'11011111' when x = '010' else

'11101111' when x = 011' else

'11110111' when x = '100' else

'11111011' when x = '101' else

'11111101' when x = '110' else

'11111110' when x = '111' else

'11111111' when others;

Y < = y, when en = ‘0' else '1111 1111' ;

End behavioral.

Just as Multiplexer, Decoder is also a Combinational circuit which transforms given inputs to a maximum number of outputs (maximum outputs equal to 2ⁿ and n are given inputs ).

A block diagram of decoder consists of input lines, one or more enable inputs and a maximum number of output lines.
To construct a decoder, we require to know the number of all possible output lines that totally depends on the given input.

So, if n represents given input lines then possible output lines would be 2ⁿ.
Decoder with three inputs would give 8 outputs (n=2,2³ that is 8).

Here are the steps to construct 3 to 8 decoder

Step 1. Now we know possible outputs for 3 inputs, so construct 3 to 8 decoder, having 3 input lines, a enable input and 8 output lines. In the below diagram, given input represented asI2, I1 and I0 , all possible outputs named as O_0, O_1, O_2,O_3, O_4, O_5,O_6& O₇ and a E were represented by Enable input.

With Enable input

Without Enable input

Step 2. Now, it turns to construct the truth table for 3 to 8 decoder. E input can be considered as a control input. Mean to say, If E equals to 0 then the decoder would be considered as disabled regardless of what inputs are, If E equals to 1 then the decoder would work as per inputs.

Truth table without E input

3 To 8 Decoder Vhdl

We can represent the following output as:

O₀ = I₀‘.I₁‘.I₂‘
O₁ = I₀.I₁‘.I₂‘

Vhdl Code For 3 To 8 Decoder Using Structural Modelling

Explanation:

In above diagram, there were three input lines along with their complements using Inverters. Each and every AND gate were holding four inputs from E, I1, I1 and I0 and producing 8 outputs.

4 To 16 Decoder Using 3 To 8 Decoder Vhdl Code

Decoder Without E

2 4 Decoder Verilog Code

Explanation:
In the above diagram, there were three input lines with their respective complements using Inverters. Each and every AND gate were holding three inputs from I1, I1 and I0 and producing 8 outputs.