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docs/stdlib/crc: minor phrasing improvement.

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Catherine 2024-04-11 06:40:30 +00:00
parent c59447c258
commit 84dff93786
2 changed files with 7 additions and 9 deletions
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12
amaranth/lib/crc/__init__.py
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@ -133,9 +133,7 @@ class Parameters:
xor_output=self._xor_output) xor_output=self._xor_output)
def residue(self): def residue(self):
"""Obtain the residual value left in the CRC register after processing a valid trailing CRC. """Obtain the residual value left in the CRC register after processing a valid trailing CRC."""
A trailing CRC data word is also known as a codeword."""
# Residue is computed by initialising to (possibly reflected) xor_output, feeding crc_width # Residue is computed by initialising to (possibly reflected) xor_output, feeding crc_width
# worth of 0 bits, then taking the (possibly reflected) output without any XOR. # worth of 0 bits, then taking the (possibly reflected) output without any XOR.
if self._reflect_output: if self._reflect_output:
@ -273,10 +271,10 @@ class Processor(Elaboratable):
computes every new bit of the CRC in parallel. computes every new bit of the CRC in parallel.
The :py:`match_detected` output may be used to validate data with a trailing CRC (also known as The :py:`match_detected` output may be used to validate data with a trailing CRC (also known as
a codeword). If the most recently processed data word(s) form the valid CRC of all the previous a codeword in coding theory). If the most recently processed data word(s) form the valid CRC of
data words since :py:`start` was asserted, the CRC register will always take on a fixed value all the previous data words since :py:`start` was asserted, the CRC register will always take on
known as the :meth:`residue <Parameters.residue>`. The :py:`match_detected` output indicates a fixed value known as the :meth:`residue <Parameters.residue>`. The :py:`match_detected` output
whether the CRC register currently contains this residue. indicates whether the CRC register currently contains this residue.
Parameters Parameters
---------- ----------

4
docs/stdlib/crc.rst
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@ -35,11 +35,11 @@ Examples
from amaranth.lib.crc.catalog import CRC16_CCITT, CRC16_USB from amaranth.lib.crc.catalog import CRC16_CCITT, CRC16_USB
# Compute a CRC in hardware using the predefined CRC16-CCITT algorithm and the data word # Compute a CRC in hardware using the predefined CRC16-CCITT algorithm and a data word
# width of 8 bits (in other words, computing it over bytes). # width of 8 bits (in other words, computing it over bytes).
m.submodules.crc16_ccitt = crc16_ccitt = CRC16_CCITT().create() m.submodules.crc16_ccitt = crc16_ccitt = CRC16_CCITT().create()
# Compute a CRC in hardware using the predefined CRC16-USB algorithm and the data word # Compute a CRC in hardware using the predefined CRC16-USB algorithm and a data word
# width of 32 bits. # width of 32 bits.
m.submodules.crc16_usb = crc16_usb = CRC16_USB(32).create() m.submodules.crc16_usb = crc16_usb = CRC16_USB(32).create()