52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
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from migen.fhdl.structure import *
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from migen.fhdl.module import Module
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from migen.genlib.cdc import MultiReg
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from migen.genlib.misc import optree
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from migen.bank.description import *
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_control_tokens = [0b1101010100, 0b0010101011, 0b0101010100, 0b1010101011]
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class CharSync(Module, AutoReg):
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def __init__(self, required_controls=8):
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self.raw_data = Signal(10)
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self.char_synced = Signal()
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self.data = Signal(10)
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self._r_char_synced = RegisterField(1, READ_ONLY, WRITE_ONLY)
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###
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raw_data1 = Signal(10)
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self.sync.pix += raw_data1.eq(self.raw_data)
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raw = Signal(20)
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self.comb += raw.eq(Cat(raw_data1, self.raw_data))
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found_control = Signal()
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control_position = Signal(max=10)
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for i in range(10):
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self.sync.pix += If(optree("|", [raw[i:i+10] == t for t in _control_tokens]),
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found_control.eq(1),
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control_position.eq(i)
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)
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control_counter = Signal(max=required_controls)
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previous_control_position = Signal(max=10)
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word_sel = Signal(max=10)
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self.sync.pix += [
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If(found_control & (control_position == previous_control_position),
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If(control_counter == (required_controls - 1),
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control_counter.eq(0),
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self.char_synced.eq(1),
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word_sel.eq(control_position)
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).Else(
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control_counter.eq(control_counter + 1)
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)
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).Else(
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control_counter.eq(0)
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),
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previous_control_position.eq(control_position)
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]
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self.specials += MultiReg(self.char_synced, self._r_char_synced.field.w)
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self.sync.pix += self.data.eq(raw >> word_sel)
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