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scrambling: document

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This commit is contained in:
Florent Kermarrec 2019-12-13 12:18:46 +01:00
parent 1147f23080
commit b49a928f21
1 changed files with 17 additions and 3 deletions
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usb3_pipe/scrambling.py
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@ -8,10 +8,14 @@ from migen import *
from litex.soc.interconnect import stream
# Scrambler Unit -----------------------------------------------------------------------------------
# Scrambler Unit (Appendix B) ----------------------------------------------------------------------
@CEInserter()
class ScramblerUnit(Module):
"""Scrambler Unit
This module generates the scrambled datas for the USB3.0 link (X^16 + X^5 + X^4 + X^3 + 1 polynom).
"""
def __init__(self):
self.value = Signal(32)
@ -73,9 +77,13 @@ class ScramblerUnit(Module):
]
self.sync += cur.eq(new)
# Scrambler ----------------------------------------------------------------------------------------
# Scrambler (Appendix B) ---------------------------------------------------------------------------
class Scrambler(Module):
"""Scrambler
This module scrambles the TX data/ctrl stream. K codes shall not be scrambled.
"""
def __init__(self):
self.sink = sink = stream.Endpoint([("data", 32), ("ctrl", 4)])
self.source = source = stream.Endpoint([("data", 32), ("ctrl", 4)])
@ -95,9 +103,15 @@ class Scrambler(Module):
)
]
# Descrambler (Scrambler + Auto-Synchronization) ---------------------------------------------------
# Descrambler (Scrambler + Auto-Synchronization) (Appendix B) --------------------------------------
class Descrambler(Module):
"""Descrambler
This module descrambles the RX data/ctrl stream. K codes shall not be scrambled. The descrambler
automatically synchronize itself to the incoming stream during the Idle handshake sequence. Once
synchronized, it will keep the current synchronization until the next reset/Idle handshake sequence.
"""
def __init__(self):
self.sink = sink = stream.Endpoint([("data", 32), ("ctrl", 4)])
self.source = source = stream.Endpoint([("data", 32), ("ctrl", 4)])