Selected assignment (with-select) in VHDL - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign output based on input using with-select.

VHDL

with input select
  output <= '1' when '1',
            '0' when [1],
            'Z' when others;

Drag options to blanks, or click blank then click option'

A'1'

B'Z'

C'0'

D'X'

Attempts:

3 left

💡 Hint

Common Mistakes

Using '1' instead of '0' for the when clause.

Forgetting the quotes around the value.

The with-select statement assigns '0' to output when input is '0'.

2fill in blank

medium

Complete the code to select the correct output value for input '2'.

VHDL

with input select
  output <= "00" when '0',
            "01" when '1',
            [1] when '2',
            "11" when others;

Drag options to blanks, or click blank then click option'

A"00"

B"11"

C"01"

D"10"

Attempts:

3 left

💡 Hint

Common Mistakes

Using output "11" for input '2' which is reserved for others.

Forgetting to use double quotes for output values.

When input is '2', output should be "10" as per the selected assignment.

3fill in blank

hard

Fix the error in the with-select statement to assign output correctly.

VHDL

with input select
  output <= '0' when '0',
            '1' when '1',
            'Z' when others
            [1]

Drag options to blanks, or click blank then click option'

A;

B,

C.

D:

Attempts:

3 left

💡 Hint

Common Mistakes

Using a comma instead of a semicolon at the end.

Omitting the punctuation entirely.

The with-select statement must end with a semicolon after the last when clause.

4fill in blank

hard

Fill both blanks to complete the with-select statement for a 2-bit output.

VHDL

with sel select
  out <= [1] when '0',
         [2] when '1',
         "11" when others;

Drag options to blanks, or click blank then click option'

A"00"

B"01"

C"10"

D"11"

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up output values for '0' and '1'.

Using single quotes instead of double quotes for output.

Output is "00" when sel is '0' and "10" when sel is '1'.

5fill in blank

hard

Fill all three blanks to complete the with-select statement for a 3-bit output.

VHDL

with address select
  data_out <= [1] when "000",
              [2] when "001",
              [3] when others;

Drag options to blanks, or click blank then click option'

A"101"

B"110"

C"111"

D"100"

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing the order of output values.

Using single quotes instead of double quotes for vectors.

data_out is "100" for "000", "101" for "001", and "111" for others.