litex/milkymist/dvisampler/chansync.py

53 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.record import Record
from migen.genlib.misc import optree
from migen.bank.description import *
from milkymist.dvisampler.common import channel_layout
class ChanSync(Module, AutoReg):
def __init__(self, nchan=3, depth=8):
self.valid_i = 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 = Record(channel_layout, name=name)
setattr(self, name, data_in)
name = "data_out" + str(i)
data_out = Record(channel_layout, name=name)
setattr(self, name, data_out)
###
fifo = SyncFIFO(10, depth)
self.add_submodule(fifo, "pix")
self.comb += [
fifo.we.eq(self.valid_i),
fifo.din.eq(Cat(*data_in.flatten())),
Cat(*data_out.flatten()).eq(fifo.dout)
]
is_control = Signal()
is_control_r = Signal()
self.sync.pix += If(fifo.readable & fifo.re, is_control_r.eq(is_control))
control_starts = Signal()
self.comb += [
is_control.eq(~data_out.de),
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.valid_i,
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)