Day-17

Counter

1. Module Declaration: The code begins by declaring a Verilog module named SimpleCounter This module has three ports:

   clk: This is the clock input signal.
   reset: This is the reset input signal.
   count: This is a 4-bit output signal representing the count value.
   

2. 4-Bit Register: Inside the module, there's a 4-bit register named count. This register holds the current count value. Registers are used to store and update data in digital circuits.

3. Always Block: The core functionality of the counter is defined within an always block. This block is sensitive to the positive edges of both the clock signal (posedge clk) and the reset signal (posedge reset). This means that the block's contents will execute whenever there is a rising edge on either the clock or the reset signal.

4. Reset Logic: Inside the always block, there's an if statement. When the reset signal is asserted (high), indicated by if (reset), the count is set to 4'b0000, effectively resetting the counter to zero. This ensures that the counter can be initialized to a known state.

5. Counting Logic: When the clock signal transitions to the positive edge (indicated by posedge clk), and the reset signal is not asserted, the counter count is incremented by 1. This simple logic increments the count value each time the clock rises.

6. Assign Statement: Finally, there's an assign statement that continuously assigns the value of count to the output count. This makes the current count value available at the module's output for external use.

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Counter - TB

1. The testbench begins with a declaration of signals:
   clk for the clock input.
   reset for the reset input.
   count to monitor the counter's output.
   

2. The SimpleCounter module is instantiated within the testbench, connecting its inputs and outputs to the corresponding signals declared in the testbench.

3. A clock signal is generated using an always block. In this case, the clock is toggled every 5 time units using #5.

4. The testbench initializes signals by setting clk to 0 and asserting the reset signal for a brief period to initialize the counter to zero.

5. Inside the initial block, the testbench monitors the count signal and displays its value using $display at each time step.

6. The simulation is run for 100 time units using $finish. You can adjust this value to control the simulation duration.