Verilog code examples pdf

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They are used only in functions and procedural blocks Verilog quits after running the simple code, it probably is not necessary, but for the sake of example it has been added to the code. StepIdentify the memories StepIdentify StepEverything else is random logic the datapaths. Using Structural Verilog. Running Verilog Code At the shell prompt, the V erilog code can be run by typing: verilog file1.v file2.v fileN.v Or, if the files, file1.v through fileN.v, are listed in a text file, each residing on a ENGRD FPGAs & Verilog TutorialVerilog Programming Styles •Structural –Textual equivalent of drawing a schematic –Uses instance statements to instantiate other modules and uses wires to connect them •Behavioral –Specify what a module does with a high-level description –Uses procedural code (e.g., in always blocks) or This is an example for two always block FSM in this Example you have Two FSMs, one is operating at posedge clk and other //operating at negedge clk. // value of d is the logical AND of // a and b // a cable (vector) ofwiresReg. This type of execution model is called “dataflow” since evaluations are In Double Data Rate (DDR2) also data transfer occur at both //the edges. module full_adder (input a, input b, input cin, output s, output cout); xor(s, a, b, cin); wire xor_a_b; wire cin_and; wire and_a_b; xor(xor_a_b, a, b); and(cin_and, cin, xor_a_b); and(and_a_b, a, b); Let’s identify the memories, datapaths, and random logic in our SMIPSv1 design. Divide and Conquer! We don’t spend much time on Behavioral Verilog because it is not a particularly good language and isn’t useful for hardware synthesis Gate-Level Circuit. The first major extension was Verilog−XL, which added a few features and implemented the infamous XL algorithm which was a very efficient method for doing gate−level simulation Verilog’s operators and continuous assignment statements: Conceptually assign’s are evaluated continuously, so whenever a value used in the RHS changes, the RHS is re-evaluated and the value of the wire/bus specified on the LHS is updated. Inverter Buffer Transmission Gate TriState Buffer Basic and Universal Gates Flip Flops SR Flip Flop JK Flip Flop D Flip Flop T Flip Flop Master-Slave (MS) Flip Flop Serial Adder assign d = a; assign d = b; wire [] A; // simple wire. it won’t synthesize. It is synthesizable Verilog Code module div_3clk(input clk,rst_n, output clk_by_3); parameter ST=2'b00Verilog It can be simulated but it will have nothing to do with hardware, i.e. Designing the Full Adder. Let’s identify the memories, datapaths, and random logic in our SMIPSv1 design. Now identify the signals which will make up the interface Verilog simulator was first used beginning in and was extended substantially through The implementation was the Verilog simulator sold by Gateway. A reg (register) is a data object that holds its value from one procedural assignment to the next.