misoc/cores/dvi_sampler/charsync.py

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