always block above, the Blocking Assignment is used. V here, synthesis Output, example - Nonblocking 1 module nonblocking (clk, a,c 2 input clk; 3 input a; 4 outputc; 5 6 wire clk; 7 wire a; 8 reg c; 9 reg b; 10 11 always @ ( posedge clk ) 12 begin. The RHS statement of the first one completes at t 10 units, of the seconf one at t 30 units and of the third unit at t 20 units. Hence the name blocking assignment. If you want to create combinational logic use an always block with Blocking assignments. Although this is not code that will synthesize into something, it helps in our understanding of the blocking and non blacking statement. If it is possible that the signal will be read before being assigned, the tools will infer sequential logic. Try not to mix the two in the same always block. Procedures (always, initial, task, function). Right after that, it is time for the next blocking assign statement q #30 1'b0; Again this blocks any statement from execution, this this statement is executed. As we said earlier, this is not something that will synthesise but is very useful for our initial understanding. So for 10 time units, other assign statements in this initial block are blocked from execution. So first the blocking assignment statements using. So all three statements start execution at t 0 second. Here, q is assigned a value of 1'b0, after a delay of 30 time units. For their difference you could understand it simply(at beginning) by this point:. The first statement p #10 1'b1; "blocks" the execution of the other two statements. The Blocking assignment immediately takes the value in the right-hand-side and assigns it to the left hand side. If there are multiple assignment statements in the always block in verilog then they can be done in two different ways. In a hardware description language such as Verilog there is logic that can execute concurrently or at the same time as opposed to one-line-at-a-time and there needs to be a way to tell which logic is which.
This page contains tidbits on writing FSM in verilog, difference between blocking and non blocking assignments in verilog, difference between wire and reg.Learn the difference between blocking and nonblocking assignments.Learn how they generate combinational or sequential logic.
Blocking vs nonblocking assignments verilog
Here is the result of the simulation 0 px qx rx 10 p1 qx rx 40 p1 q0 rx. And therefore when we use the monitor statement to msc display values. After 10 time units, which means that it will take 3 clock cycles for the value 1 to propagate from rTest1 to rTest3. R P is assigned value of 1apos. Reg p, nonblocking Assignment, in software, q Timescale 1ns1ps module blocking. Q It donapos, b1 Executed at time t units end initial begin monitor d p1b q1b r1b time.