Verilog

Introduction

Dipping my toe into this now I own an fpga

Hello World

This is the first program. There are two files to get it to work, a pcf file which defines things you use in the verilog file. Currently my understanding is it maps hardware to names which you can reference in the verilog file. Here is the project. I only use two buttons in the example but there are four shown for the second example

Truth Table

For the requirements we have only light when both buttons are pressed. This was documented with a circuit diagram and a truth table

Boolean Algebra

For Boolean logic there are 4 operators

PCF Physical Constraints File

Could not find a lexer but here we define names to io pins. You lookup the pin in the datasheet, in my case a ice40UP5K-B-EVN and you assign a name.

#LED 
set_io              led_0  41

#HEADER B I/O
set_io  -pullup yes pmod_0 23
set_io  -pullup yes pmod_1 25

Here is my first program, it defines two input buttons and 1 LED in a module called and_gate. The value of LED is true when pmod_0 and pmod_1 are true.

module and_gate (
    // inputs
    input   pmod_0,
    input   pmod_1,

    // Outputs
    output  led_0
);

    assign led_0 = ~pmod_0 & ~pmod_1;
    
endmodule