misoc/cores/dvi_sampler/charsync.py

   1 from functools import reduce
   2 from operator import or_
   3
   4 from migen import *
   5 from migen.genlib.cdc import MultiReg
   6
   7 from misoc.interconnect.csr import *
   8 from misoc.cores.dvi_sampler.common import control_tokens
   9
  10
  11 class CharSync(Module, AutoCSR):
  12     def __init__(self, required_controls=8):
  13         self.raw_data = Signal(10)
  14         self.synced = Signal()
  15         self.data = Signal(10)
  16
  17         self._char_synced = CSRStatus()
  18         self._ctl_pos = CSRStatus(bits_for(9))
  19
  20         ###
  21
  22         raw_data1 = Signal(10)
  23         self.sync.pix += raw_data1.eq(self.raw_data)
  24         raw = Signal(20)
  25         self.comb += raw.eq(Cat(raw_data1, self.raw_data))
  26
  27         found_control = Signal()
  28         control_position = Signal(max=10)
  29         self.sync.pix += found_control.eq(0)
  30         for i in range(10):
  31             self.sync.pix += If(reduce(or_, [raw[i:i+10] == t for t in control_tokens]),
  32                   found_control.eq(1),
  33                   control_position.eq(i)
  34             )
  35
  36         control_counter = Signal(max=required_controls)
  37         previous_control_position = Signal(max=10)
  38         word_sel = Signal(max=10)
  39         self.sync.pix += [
  40             If(found_control & (control_position == previous_control_position),
  41                 If(control_counter == (required_controls - 1),
  42                     control_counter.eq(0),
  43                     self.synced.eq(1),
  44                     word_sel.eq(control_position)
  45                 ).Else(
  46                     control_counter.eq(control_counter + 1)
  47                 )
  48             ).Else(
  49                 control_counter.eq(0)
  50             ),
  51             previous_control_position.eq(control_position)
  52         ]
  53         self.specials += MultiReg(self.synced, self._char_synced.status)
  54         self.specials += MultiReg(word_sel, self._ctl_pos.status)
  55
  56         self.sync.pix += self.data.eq(raw >> word_sel)