litex/milkymist/dvisampler/chansync.py
2013-03-22 18:37:10 +01:00

51 lines
1.6 KiB
Python

from migen.fhdl.structure import *
from migen.fhdl.module import Module
from migen.genlib.cdc import MultiReg
from migen.genlib.fifo import SyncFIFO
from migen.genlib.misc import optree
from migen.bank.description import *
_control_tokens = [0b1101010100, 0b0010101011, 0b0101010100, 0b1010101011]
class ChanSync(Module, AutoReg):
def __init__(self, nchan=3, depth=8):
self.char_synced = Signal()
self.chan_synced = Signal()
self._r_channels_synced = RegisterField(1, READ_ONLY, WRITE_ONLY)
lst_control_starts = []
all_control_starts = Signal()
for i in range(nchan):
name = "data_in" + str(i)
data_in = Signal(10, name=name)
setattr(self, name, data_in)
name = "data_out" + str(i)
data_out = Signal(10, name=name)
setattr(self, name, data_out)
###
fifo = SyncFIFO(10, depth)
self.add_submodule(fifo, "pix")
self.comb += [
fifo.we.eq(self.char_synced),
fifo.din.eq(data_in),
data_out.eq(fifo.dout)
]
is_control = Signal()
is_control_r = Signal()
self.sync.pix += If(fifo.re, is_control_r.eq(is_control))
control_starts = Signal()
self.comb += [
is_control.eq(optree("|", [data_out == t for t in _control_tokens])),
control_starts.eq(is_control & ~is_control_r),
fifo.re.eq(~is_control | all_control_starts)
]
lst_control_starts.append(control_starts)
self.comb += all_control_starts.eq(optree("&", lst_control_starts))
self.sync.pix += If(~self.char_synced,
self.chan_synced.eq(0)
).Elif(all_control_starts, self.chan_synced.eq(1))
self.specials += MultiReg(self.chan_synced, self._r_channels_synced.field.w)