When to use non-blocking (sequential) in Verilog - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to assign a value to 'q' using non-blocking assignment.

Verilog

always @(posedge clk) begin
  q [1] d;
end

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

A==

B<=

C=

D->

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' instead of '<=' causes combinational behavior.

Non-blocking assignment uses '<=' to update registers sequentially on clock edges.

2fill in blank

medium

Complete the code to correctly update two registers sequentially using non-blocking assignments.

Verilog

always @(posedge clk) begin
  a [1] b;
  b [1] a;
end

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

A<=

B=

C==

D+=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' causes immediate update and incorrect swapping.

Non-blocking assignments '<=' ensure both 'a' and 'b' update simultaneously after the clock edge.

3fill in blank

hard

Fix the error in the code by choosing the correct assignment operator for sequential logic.

Verilog

always @(posedge clk) begin
  count [1] count + 1;
end

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

A<=

B+=

C==

D=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' causes combinational logic and incorrect counting.

Non-blocking assignment '<=' is required to update 'count' correctly on clock edges.

4fill in blank

hard

Fill both blanks to create a sequential process that updates 'x' and 'y' correctly.

Verilog

always @(posedge clk) begin
  x [1] y;
  y [2] x + 1;
end

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

A<=

B=

C+=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing '=' and '<=' causes unexpected behavior.

Both assignments use non-blocking '<=' to ensure sequential updates without race conditions.

5fill in blank

hard

Fill all three blanks to implement a sequential shift register using non-blocking assignments.

Verilog

always @(posedge clk) begin
  reg3 [1] reg2;
  reg2 [2] reg1;
  reg1 [3] data_in;
end

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

A=

B<=

C==

D+=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' causes immediate updates and incorrect shifting.

Non-blocking assignments '<=' are used to update all registers sequentially on the clock edge.