Systemverilog always forever

• What is a clock always statement in SystemVerilog?

  Talk about “clocked always statements”, which generate combinational logic gates and flip-flops Unfortunately, SystemVerilog does not have well-defined semantics for describing flip-flops and finite state machines (FSMs)

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• What happens if I don't follow SystemVerilog's idioms?

  Instead, SystemVerilog relies on idioms to describe flip-flops and FSMs (i.e., the use of coding templates that synthesis tools will interpret to mean flip-flops and FSMs) If you do not follow these “templates”, your code may still simulate correctly, but may produce incorrect hardware always_ff @(posedge clk)

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• Does SystemVerilog have semantics for describing flip-flops and finite state machines?

  Unfortunately, SystemVerilog does not have well-defined semantics for describing flip-flops and finite state machines (FSMs) Instead, SystemVerilog relies on idioms to describe flip-flops and FSMs (i.e., the use of coding templates that synthesis tools will interpret to mean flip-flops and FSMs)

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• What are always@ blocks in Verilog?

  Sections 1.1 to 1.6 discuss always@ blocks in Verilog, and when to use the two major flavors of always@ block, namely the always@( * ) and always@(posedge Clock) block. always@ blocks are used to describe events that should happen under certain conditions. always@ blocks are always followed by a set of parentheses, a begin, some code, and an end.

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• [PDF File]Lecture 3: Continuation of SystemVerilog

  https://info.5y1.org/systemverilog-always-forever_1_a493cf.html

  • Talk about “clocked always statements”, which generate combinational logic gates and flip-flops • Unfortunately, SystemVerilog does not have well-defined semantics for describing flip-flops and finite state machines (FSMs) • Instead, SystemVerilog relies on idioms to describe flip-flops and FSMs (i.e., the use of coding templates

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• [PDF File]A Brief Introduction to SystemVerilog

  https://info.5y1.org/systemverilog-always-forever_1_1461a1.html

  •Variant of alwaysblock called always_ff –Indicates that block will be sequential logic (flip flops) •Procedural block occurs only on a signal’s edge –@(posedge …)or @(negedge …) always_ff @(posedge clk, negedge reset_n) begin // This procedure will be executed // anytime clk goes from 0 to 1 // or anytime reset_n goes from 1 to 0 end

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• [PDF File]Verilog: always @ Blocks - University of California, Berkeley

  https://info.5y1.org/systemverilog-always-forever_1_dae1b8.html

  They are not otherwise. Elements in an always@ block are set/updated in sequentially and in parallel, depending on the type of assignment used. There are two types of assignments:

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• [PDF File]Lecture 4: Continuation of SystemVerilog

  https://info.5y1.org/systemverilog-always-forever_1_f7990d.html

  example with just one “always_ff” statement (no separate “assign” statement)? • Let’s assume we still want “q” to be “1” when we are in state “S0”. • Can we put the logic for “q” instead the “always_ff” statement? • Yes, but a flip-flop will be created for “q”! Continuing with the FSM Example

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• [PDF File]Synthesizing SystemVerilog - Sutherland HDL

  https://info.5y1.org/systemverilog-always-forever_1_0ce79a.html

  6o 3f 0 Stu Sutherland Sutherland HDL Don Mills Microchip New Synthesizable Variable Data Types Useful synthesizable variable types logic— 4-state variable, user-defined size (replaces reg)

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• [PDF File]An Overview of SystemVerilog - University of California, Berkeley

  https://info.5y1.org/systemverilog-always-forever_1_856d20.html

  reg for LHS of code inside always @ blocks Both: the containing statement determines if the net is the direct output of a register or combinational logic SystemVerilog logic for LHS of assign statements logic for LHS of code inside always @ blocks wire a; reg b, c; assign a = ____; always @(* ) b = ____; always @(posedge clk) c

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