examples/wb_initiator.py

   1 from random import Random
   2
   3 from migen.fhdl.structure import *
   4 from migen.fhdl import autofragment
   5 from migen.bus.transactions import *
   6 from migen.bus import wishbone
   7 from migen.sim.generic import Simulator
   8 from migen.sim.icarus import Runner
   9
  10 def my_generator():
  11         prng = Random(92837)
  12         for x in range(10):
  13                 t = TWrite(x, 2*x)
  14                 yield t
  15                 print("Wrote in " + str(t.latency) + " cycle(s)")
  16                 for delay in range(prng.randrange(0, 3)):
  17                         yield None
  18         for x in range(10):
  19                 t = TRead(x)
  20                 yield t
  21                 print("Read " + str(t.data) + " in " + str(t.latency) + " cycle(s)")
  22                 for delay in range(prng.randrange(0, 3)):
  23                         yield None
  24
  25 class MyPeripheral:
  26         def __init__(self):
  27                 self.bus = wishbone.Interface()
  28                 self.ack_en = Signal()
  29                 self.prng = Random(763627)
  30
  31         def do_simulation(self, s):
  32                 # Only authorize acks on certain cycles to simulate variable latency
  33                 s.wr(self.ack_en, self.prng.randrange(0, 2))
  34
  35         def get_fragment(self):
  36                 comb = [
  37                         self.bus.ack.eq(self.bus.cyc & self.bus.stb & self.ack_en),
  38                         self.bus.dat_r.eq(self.bus.adr + 4)
  39                 ]
  40                 return Fragment(comb, sim=[self.do_simulation])
  41
  42 def main():
  43         master = wishbone.Initiator(my_generator())
  44         slave = MyPeripheral()
  45         tap = wishbone.Tap(slave.bus)
  46         intercon = wishbone.InterconnectPointToPoint(master.bus, slave.bus)
  47         def end_simulation(s):
  48                 s.interrupt = master.done
  49         fragment = autofragment.from_local() + Fragment(sim=[end_simulation])
  50         sim = Simulator(fragment, Runner())
  51         sim.run()
  52
  53 main()