[Verilog] Sequential/parallel block

목차

Sequential block(순차블록): begin-end

• Declaration of data, local parameter, parameter, let, and statements
• r은 순차적으로 #d마다 변화합니다.

parameter d = 50;
reg [7:0] r; // a waveform controlled
 
begin // by sequential delay
        #d r = ’h35;
        #d r = ’hE2;
        #d r = ’h00;
        #d r = ’hF7;
        #d -> end_wave;// trigger an event
        // called end_wave
end

 

Parallel block(병렬블록): fork-join

• The timing controls in a fork-join block do not have to be ordered sequentially in time
• 순차블록과 달리 fork-join 구문 내 모든 문장의  # 딜레이가 동시에 시작합니다.

fork
        #50 r = ’h35;
        #100 r = ’hE2;
        #150 r = ’h00;
        #200 r = ’hF7;
        #250 -> end_wave;
join

// joining of events
begin
        fork
               @Aevent;
               @Bevent;
        join
        areg = breg; // will start after
end // the 2 events done