misoclib/dvisampler/charsync.py

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