[myhdl-list] Johnson counter page

[George P. <ge...@ga...>]

Thanks for the example of the Johnson Counter.

http://myhdl.jandecaluwe.com/doku.php/cookbook:jc2

Could you have used an @always block if you pulled the state variables 
out of the logic() function and put them in the enclosing scope, as 
illustrated below?

I noticed that the state variables are not manipulated by the .next 
operator, but instead directly assigned (combinatorially, as you say). I 
didn't know this was possible with variables that would end up in the 
verilog output!

Please tell us more about your preferred coding style and why you 
recommend it!

Thanks,
George


from myhdl import *
 
ACTIVE = 0
DirType = enum('RIGHT', 'LEFT')

def jc2(left,right,stop,clk,q):
     ...
     ...
     ...
     dir = Signal(DirType.LEFT)
     run = Signal(bool(False))

     @always(clk.posedge)
     def logic():
          if right == ACTIVE:
               dir = DirType.RIGHT
               run = True
          ...
          ...
          ...
     return instances()