语法错误,谢谢!

armwork · 发表于 2009-6-30 10:40:35

always @(state or  X)
begin
case (state)
   S0: if(X)
      next_state =  S1;
else
      next_state =  S0;
S1: begin //delay some positive edges of clock
         repeat(`Y2RDELAY) @(posedge clock) ;
         next_state =  S2;
      end
S2: begin //delay some positive edges of clock
         repeat(`R2GDELAY) @(posedge clock)
         next_state =  S3;
      end
S3: if( X)
         next_state =  S3;
      else
         next_state =  S4;
S4: begin //delay some positive edges of clock
         repeat(`Y2RDELAY) @(posedge clock) ;
         next_state =  S0;
      end
default: next_state =  S0;
endcase
end

armwork · 发表于 2009-6-30 10:43:42

代码是摘自夏老师翻译的VERILOG HDL数字设计与综合(第二版),我用的是XILINX软件,合成时候语法错误;但MODELSIM可以仿真.

语法错误:Unsupported Event Control Statement: repeat(`Y2RDELAY) @(posedge clock)

谢谢!

wangli1013 · 发表于 2009-7-2 10:01:56

repeat(`Y2RDELAY) @(posedge clock)
这个是仿真的时候用的，综合不了的。。。

armwork · 发表于 2009-7-2 10:43:01

谢谢,如果想综合该怎么写呢?

Cliff · 发表于 2009-7-2 12:53:16

你心中要有硬件
HDL 描述的是硬件，而不是算法

armwork · 发表于 2009-7-2 16:16:46

谢谢,代码本来的意思是延迟后切换到另外状态,请问这个延迟怎么实现呢? 用计数器吗?

wangli1013 · 发表于 2009-7-2 16:18:27

恩是的可以用计数器延时啊

armwork · 发表于 2009-7-2 17:36:09

用计时器延时依然不好写?总感觉别扭:

always @(state or  X) 这里面并没有时钟信号,该怎么写呢,想不出来.
如果改成always @(state or  X or posedge clk)硬件也没办法综合．

只能这样写：
always @(posedge clk）
begin
   case (state)
S0: if(X)
         next_state =  S1;
      else
         next_state =  S0;
      S1: begin //delay some positive edges of clock
            repeat(`Y2RDELAY) @(posedge clock) ;
            next_state =  S2;
         end

end

armwork · 发表于 2009-7-2 17:41:10

always @(posedge clk）
begin
   case (state)
      S0: if(X)
         next_state =  S1;
      else
         begin
            next_state =  S0;
            cnt<=0;
         end
      S1: begin //delay some positive edges of clock
            if (cnt==10)
               begin
                  next_state =  S2;
                  cnt<=0;
               end
            else
               cnt<=cnt+1;
         end

end

这样写对吗，很别扭？谢谢

语法错误,谢谢!

阿莫论坛20周年了！感谢大家的支持与爱护！！