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##
## This file is part of the libsigrokdecode project.
##
## Copyright (C) 2015 Petteri Aimonen <jpa@sigrok.mail.kapsi.fi>
##
## 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 = 'stepper_motor'
name = 'Stepper motor'
longname = 'Stepper motor position / speed'
desc = 'Absolute position and movement speed from step/dir.'
license = 'gplv2+'
inputs = ['logic']
outputs = ['stepper_motor']
channels = (
{'id': 'step', 'name': 'Step', 'desc': 'Step pulse'},
{'id': 'dir', 'name': 'Direction', 'desc': 'Direction select'},
)
options = (
{'id': 'unit', 'desc': 'Unit', 'default': 'steps',
'values': ('steps', 'mm')},
{'id': 'steps_per_mm', 'desc': 'Steps per mm', 'default': 100.0},
)
annotations = (
('speed', 'Speed'),
('position', 'Position')
)
annotation_rows = (
('speed', 'Speed', (0,)),
('position', 'Position', (1,)),
)
def __init__(self, **kwargs):
self.oldstep = None
self.prev_step_ss = None
self.pos = 0
self.prev_speed = None
self.prev_pos = None
def start(self):
self.out_ann = self.register(srd.OUTPUT_ANN)
if self.options['unit'] == 'steps':
self.scale = 1
self.format = '%0.0f'
self.unit = 'steps'
else:
self.scale = self.options['steps_per_mm']
self.format = '%0.2f'
self.unit = 'mm'
def step(self, ss, direction):
if self.prev_step_ss is not None:
delta = ss - self.prev_step_ss
speed = self.samplerate / delta / self.scale
speed_txt = self.format % speed
pos_txt = self.format % (self.pos / self.scale)
self.put(self.prev_step_ss, ss, self.out_ann,
[0, [speed_txt + ' ' + self.unit + '/s', speed_txt]])
self.put(self.prev_step_ss, ss, self.out_ann,
[1, [pos_txt + ' ' + self.unit, pos_txt]])
self.pos += (1 if direction else -1)
self.prev_step_ss = ss
def metadata(self, key, value):
if key == srd.SRD_CONF_SAMPLERATE:
self.samplerate = value
def decode(self, ss, es, data):
if not self.samplerate:
raise SamplerateError('Cannot decode without samplerate.')
for (self.samplenum, (step, direction)) in data:
if step == 1 and self.oldstep == 0:
self.step(self.samplenum, direction)
self.oldstep = step
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