How to get outputs/pulses when counter reaches two particular values? - verilog

Question

I have created a counter that counts up to 30. I have an output signal out. At two particular counts, i.e., when counter reaches 10 (first) and when counter reaches 15 (second), I want the output to become low. Somehow I'm missing a basic logic here as only at one particular count (either at 10 or 15) I'm able to make the output zero.
Here is the code
module user_def_pulse(
output integer counter,
output reg out,
input clk, reset
);
parameter no_of_counts = 30;
parameter first = 10;
parameter second = 15;
initial
begin
counter = 0;
out = 1'b0;
end
always #(posedge clk)
begin
if (reset)
begin
counter <= 1'b0;
end
else if (counter == no_of_counts)
begin
counter <= 1'b0;
out <= 1'b0;
end
else
begin
if ((counter == first) || (counter == second))
out <= 1'b0;
else
begin
counter <= counter + 1;
out <= 1'b1;
$display($time," The value of counter is %d", counter);
end
end
end
endmodule
Here is the test bench
module user_def_pulse_tb(
);
parameter time_period = 10;
wire [31:0] COUNTER;
wire OUT;
reg CLK, RESET;
user_def_pulse udp1 (.counter(COUNTER), .out(OUT), .clk(CLK), .reset(RESET));
initial
begin
CLK = 1'b0;
RESET = 1'b1;
#20 RESET = 1'b0;
end
always
#time_period CLK = ~CLK;
endmodule
Here is the output waveform.

Answer 1

The problem with your code is that is stops incrementing the counter as soon as it hits the first value. You need to keep incrementing the counter. I moved the increment outside of the if ((counter == first) || ... clause.
always #(posedge clk) begin
if (reset) begin
counter <= 1'b0;
end else if (counter == no_of_counts) begin
counter <= 1'b0;
out <= 1'b0;
end else begin
counter <= counter + 1;
$display($time," The value of counter is %d", counter);
if ((counter == first) || (counter == second)) begin
out <= 1'b0;
end else begin
out <= 1'b1;
end
end
end