How do you write a counter code for Verilog?

Electronic Counter Example

1. module counter (input clk, // Declare input port for the clock to allow counter to count up.
2. input rstn, // Declare input port for the reset to allow the counter to be reset to 0 when required.
3. output reg[3:0] out); // Declare 4-bit output port to get the counter values.

How do you change an up counter to a down counter?

To convert the up counter in Fig. 5.6. 1 to count DOWN instead, is simply a matter of modifying the connections between the flip-flops. By taking both the output lines and the CK pulse for the next flip-flop in sequence from the Q output as shown in Fig.

What is an up down counter?

Counters are used in many different applications. Some count up from zero and provide a change in state of output upon reaching a predetermined value; others count down from a preset value to zero to provide an output state change. The counters are synchronous, but they are asynchronously presettable. …

What is a counter in Verilog?

Counters use sequential logic to count clock pulses. You can implicitly implement a counter with a Register Inference. The Quartus II software can infer a counter from a Conditional (“If-Else”) Statement that specifies logic that adds or subtracts a value from the signal or register.

How can you tell if a countertop is up or down?

The only difference between an up-counter and a down counter stems from the ports that are connected to the display. For up-counters, the non-inverted output, Q, is connected to the display. Whereas for a down counter, the inverted output, nQ, is connected to the display.

What does a for loop do in synthesizable code?

For loops in synthesizable code are used for expanding replicated logic. They are simply a way of shrinking the amount of code that is written by the hardware designer. They do not loop like a C program loops. They only expand replicated logic.

What are the requirements for a for loop in verilog?

The keyword for is used to specify this type of loop and has three parts:

• Initial condition to specify initial values of signals.
• A check to evaluate if the given condition is true.
• Update control variable for the next iteration.

How to make a 4 bit Verilog counter?

In this post, I have shared the Verilog code for a 4 bit up/down counter. The module has 3 inputs – Clk, reset which is active high and a UpOrDown mode input. The output is Counter which is 4 bit in size. //When Up mode is selected, counter counts from 0 to 15 and then again from 0 to 15.

How is the direction of the Count selected in Verilog?

The direction of the count (mode) is selected using a single bit input. In this post, I have shared the Verilog code for a 4 bit up/down counter. The module has 3 inputs – Clk, reset which is active high and a UpOrDown mode input. The output is Counter which is 4 bit in size.

How to write Verilog code for digital circuits?

Programmable Digital Delay Timer in Verilog HDL 5. Verilog code for basic logic components in digital circuits 6. Verilog code for 32-bit Unsigned Divider 7. Verilog code for Fixed-Point Matrix Multiplication

What should the up / down counter code look like?

Your up/down counter needs an additional clock input. The updown input should be a single bit, not eight bits. The code for the counter should look similar to that of the pulse generator. In every clock cycle, one of the following should happen: