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rtio: export CDC modules

This commit is contained in:
Sebastien Bourdeauducq 2016-10-22 13:03:10 +08:00
parent 67c19ab178
commit 449d1c4dc6
2 changed files with 72 additions and 67 deletions

View File

@ -0,0 +1,68 @@
from migen import *
from migen.genlib.cdc import *
__all__ = ["GrayCodeTransfer", "RTIOCounter", "BlindTransfer"]
# note: transfer is in rtio/sys domains and not affected by the reset CSRs
class GrayCodeTransfer(Module):
def __init__(self, width):
self.i = Signal(width) # in rtio domain
self.o = Signal(width) # in sys domain
# # #
# convert to Gray code
value_gray_rtio = Signal(width)
self.sync.rtio += value_gray_rtio.eq(self.i ^ self.i[1:])
# transfer to system clock domain
value_gray_sys = Signal(width)
self.specials += [
NoRetiming(value_gray_rtio),
MultiReg(value_gray_rtio, value_gray_sys)
]
# convert back to binary
value_sys = Signal(width)
self.comb += value_sys[-1].eq(value_gray_sys[-1])
for i in reversed(range(width-1)):
self.comb += value_sys[i].eq(value_sys[i+1] ^ value_gray_sys[i])
self.sync += self.o.eq(value_sys)
class RTIOCounter(Module):
def __init__(self, width):
self.width = width
# Timestamp counter in RTIO domain
self.value_rtio = Signal(width)
# Timestamp counter resynchronized to sys domain
# Lags behind value_rtio, monotonic and glitch-free
self.value_sys = Signal(width)
# # #
# note: counter is in rtio domain and never affected by the reset CSRs
self.sync.rtio += self.value_rtio.eq(self.value_rtio + 1)
gt = GrayCodeTransfer(width)
self.submodules += gt
self.comb += gt.i.eq(self.value_rtio), self.value_sys.eq(gt.o)
class BlindTransfer(Module):
def __init__(self):
self.i = Signal()
self.o = Signal()
ps = PulseSynchronizer("rio", "rsys")
ps_ack = PulseSynchronizer("rsys", "rio")
self.submodules += ps, ps_ack
blind = Signal()
self.sync.rio += [
If(self.i, blind.eq(1)),
If(ps_ack.o, blind.eq(0))
]
self.comb += [
ps.i.eq(self.i & ~blind),
ps_ack.i.eq(ps.o),
self.o.eq(ps.o)
]

View File

@ -3,75 +3,12 @@ from operator import and_
from migen import *
from migen.genlib.record import Record
from migen.genlib.cdc import *
from migen.genlib.fifo import AsyncFIFO
from migen.genlib.resetsync import AsyncResetSynchronizer
from misoc.interconnect.csr import *
from artiq.gateware.rtio import rtlink
# note: transfer is in rtio/sys domains and not affected by the reset CSRs
class _GrayCodeTransfer(Module):
def __init__(self, width):
self.i = Signal(width) # in rtio domain
self.o = Signal(width) # in sys domain
# # #
# convert to Gray code
value_gray_rtio = Signal(width)
self.sync.rtio += value_gray_rtio.eq(self.i ^ self.i[1:])
# transfer to system clock domain
value_gray_sys = Signal(width)
self.specials += [
NoRetiming(value_gray_rtio),
MultiReg(value_gray_rtio, value_gray_sys)
]
# convert back to binary
value_sys = Signal(width)
self.comb += value_sys[-1].eq(value_gray_sys[-1])
for i in reversed(range(width-1)):
self.comb += value_sys[i].eq(value_sys[i+1] ^ value_gray_sys[i])
self.sync += self.o.eq(value_sys)
class _RTIOCounter(Module):
def __init__(self, width):
self.width = width
# Timestamp counter in RTIO domain
self.value_rtio = Signal(width)
# Timestamp counter resynchronized to sys domain
# Lags behind value_rtio, monotonic and glitch-free
self.value_sys = Signal(width)
# # #
# note: counter is in rtio domain and never affected by the reset CSRs
self.sync.rtio += self.value_rtio.eq(self.value_rtio + 1)
gt = _GrayCodeTransfer(width)
self.submodules += gt
self.comb += gt.i.eq(self.value_rtio), self.value_sys.eq(gt.o)
class _BlindTransfer(Module):
def __init__(self):
self.i = Signal()
self.o = Signal()
ps = PulseSynchronizer("rio", "rsys")
ps_ack = PulseSynchronizer("rsys", "rio")
self.submodules += ps, ps_ack
blind = Signal()
self.sync.rio += [
If(self.i, blind.eq(1)),
If(ps_ack.o, blind.eq(0))
]
self.comb += [
ps.i.eq(self.i & ~blind),
ps_ack.i.eq(ps.o),
self.o.eq(ps.o)
]
from artiq.gateware.rtio.cdc import *
# CHOOSING A GUARD TIME
@ -229,7 +166,7 @@ class _OutputManager(Module):
interface.stb.eq(dout_stb & dout_ack)
]
busy_transfer = _BlindTransfer()
busy_transfer = BlindTransfer()
self.submodules += busy_transfer
self.comb += [
busy_transfer.i.eq(interface.stb & interface.busy),
@ -291,7 +228,7 @@ class _InputManager(Module):
fifo.re.eq(self.re)
]
overflow_transfer = _BlindTransfer()
overflow_transfer = BlindTransfer()
self.submodules += overflow_transfer
self.comb += [
overflow_transfer.i.eq(fifo.we & ~fifo.writable),
@ -398,7 +335,7 @@ class RTIO(Module):
allow_reset_less=True))
# Managers
self.submodules.counter = _RTIOCounter(full_ts_width - fine_ts_width)
self.submodules.counter = RTIOCounter(full_ts_width - fine_ts_width)
i_datas, i_timestamps = [], []
o_statuses, i_statuses = [], []