mirror of
https://github.com/DreamSourceLab/DSView.git
synced 2025-01-13 13:32:53 +08:00
84 lines
2.8 KiB
Python
84 lines
2.8 KiB
Python
|
##
|
||
|
|
## This file is part of the libsigrokdecode project.
|
||
|
|
##
|
||
|
|
## Copyright (C) 2013 Uwe Hermann <uwe@hermann-uwe.de>
|
||
|
|
##
|
||
|
|
## This program is free software; you can redistribute it and/or modify
|
||
|
|
## it under the terms of the GNU General Public License as published by
|
||
|
|
## the Free Software Foundation; either version 2 of the License, or
|
||
|
|
## (at your option) any later version.
|
||
|
|
##
|
||
|
|
## This program is distributed in the hope that it will be useful,
|
||
|
|
## but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
|
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
|
|
## GNU General Public License for more details.
|
||
|
|
##
|
||
|
|
## You should have received a copy of the GNU General Public License
|
||
|
|
## along with this program; if not, write to the Free Software
|
||
|
|
## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
||
|
|
##
|
||
|
|
|
||
|
|
import sigrokdecode as srd
|
||
|
|
|
||
|
|
class SamplerateError(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
class Decoder(srd.Decoder):
|
||
|
|
api_version = 2
|
||
|
|
id = 'guess_bitrate'
|
||
|
|
name = 'Guess bitrate'
|
||
|
|
longname = 'Guess bitrate/baudrate'
|
||
|
|
desc = 'Guess the bitrate/baudrate of a UART (or other) protocol.'
|
||
|
|
license = 'gplv2+'
|
||
|
|
inputs = ['logic']
|
||
|
|
outputs = ['guess_bitrate']
|
||
|
|
channels = (
|
||
|
|
{'id': 'data', 'name': 'Data', 'desc': 'Data line'},
|
||
|
|
)
|
||
|
|
annotations = (
|
||
|
|
('bitrate', 'Bitrate / baudrate'),
|
||
|
|
)
|
||
|
|
|
||
|
|
def putx(self, data):
|
||
|
|
self.put(self.ss_edge, self.samplenum, self.out_ann, data)
|
||
|
|
|
||
|
|
def __init__(self):
|
||
|
|
self.olddata = None
|
||
|
|
self.ss_edge = None
|
||
|
|
self.first_transition = True
|
||
|
|
self.bitwidth = None
|
||
|
|
|
||
|
|
def start(self):
|
||
|
|
self.out_ann = self.register(srd.OUTPUT_ANN)
|
||
|
|
|
||
|
|
def metadata(self, key, value):
|
||
|
|
if key == srd.SRD_CONF_SAMPLERATE:
|
||
|
|
self.samplerate = value
|
||
|
|
|
||
|
|
def decode(self, ss, es, logic):
|
||
|
|
if not self.samplerate:
|
||
|
|
raise SamplerateError('Cannot decode without samplerate.')
|
||
|
|
for (self.samplenum, pins) in logic:
|
||
|
|
(data,) = pins
|
||
|
|
logic.logic_mask = 1
|
||
|
|
logic.cur_pos = self.samplenum
|
||
|
|
logic.edge_index = -1
|
||
|
|
|
||
|
|
# Initialize first self.olddata with the first sample value.
|
||
|
|
if self.olddata is None:
|
||
|
|
self.olddata = data
|
||
|
|
continue
|
||
|
|
|
||
|
|
# Get the smallest distance between two transitions
|
||
|
|
# and use that to calculate the bitrate/baudrate.
|
||
|
|
if self.first_transition:
|
||
|
|
self.ss_edge = self.samplenum
|
||
|
|
self.first_transition = False
|
||
|
|
else:
|
||
|
|
b = self.samplenum - self.ss_edge
|
||
|
|
if self.bitwidth is None or b < self.bitwidth:
|
||
|
|
self.bitwidth = b
|
||
|
|
bitrate = int(float(self.samplerate) / float(b))
|
||
|
|
self.putx([0, ['%d' % bitrate]])
|
||
|
|
self.ss_edge = self.samplenum
|