First VHDL design (AND gate) - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the AND gate entity name.

VHDL

entity [1] is
  Port ( A : in STD_LOGIC;
         B : in STD_LOGIC;
         Y : out STD_LOGIC);
end [1];

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Axor_gate

Bor_gate

Cnot_gate

Dand_gate

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different gate name like or_gate or not_gate.

Mismatching entity name and end statement.

The entity name must match the design name. Here, the AND gate is named and_gate.

2fill in blank

medium

Complete the architecture header to define the AND gate behavior.

VHDL

architecture Behavioral of and_gate is
begin
  [1] : process(A, B)
  begin
    Y <= A and B;
  end process [1];
end Behavioral;

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ANOT_Process

BOR_Process

CAND_Process

DXOR_Process

Attempts:

3 left

💡 Hint

Common Mistakes

Using process names that do not match the logic function.

Leaving the process name blank.

The process name should be descriptive. Here, AND_Process fits the AND gate behavior.

3fill in blank

hard

Fix the error in the signal assignment inside the process.

VHDL

architecture Behavioral of and_gate is
begin
  AND_Process : process(A, B)
  begin
    Y <= [1];
  end process AND_Process;
end Behavioral;

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AA and B

BA or B

CA nand B

DA xor B

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'or' or 'xor' instead of 'and'.

Using 'nand' which is the inverse of 'and'.

The AND gate output is the logical AND of inputs A and B, so Y <= A and B; is correct.

4fill in blank

hard

Fill both blanks to complete the port declaration for inputs and output.

VHDL

entity and_gate is
  Port ( A : [1] STD_LOGIC;
         B : [1] STD_LOGIC;
         Y : [2] STD_LOGIC);
end and_gate;

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Ain

Bout

Cbuffer

Dinout

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'out' for inputs or 'in' for outputs.

Using 'buffer' or 'inout' incorrectly.

Inputs use in direction and outputs use out direction in VHDL port declarations.

5fill in blank

hard

Fill all three blanks to complete the architecture with concurrent signal assignment.

VHDL

architecture Behavioral of and_gate is
begin
  [1] <= [2] [3] B;
end Behavioral;

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AY

BA

Cand

Dor

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'or' instead of 'and'.

Swapping output and input signals.

The concurrent assignment sets output Y to the logical AND of inputs A and B.