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# -*- coding: utf-8 -*-
#
# PROFIBUS DP - Communication Processor PHY access library
#
# Copyright (c) 2013-2016 Michael Buesch <m@bues.ch>
#
# Licensed under the terms of the GNU General Public License version 2,
# or (at your option) any later version.
#
from __future__ import division, absolute_import, print_function, unicode_literals
from pyprofibus.compat import *
import time
import sys
from collections import deque
from pyprofibus.util import *
__all__ = [
"PhyError",
"CpPhy",
]
class PhyError(ProfibusError):
"""PHY exception.
"""
class CpPhy(object):
"""PROFIBUS CP PHYsical layer base class.
"""
PFX = "PHY: "
# Profibus baud-rates
BAUD_9600 = 9600
BAUD_19200 = 19200
BAUD_45450 = 45450
BAUD_93750 = 93750
BAUD_187500 = 187500
BAUD_500000 = 500000
BAUD_1500000 = 1500000
BAUD_3000000 = 3000000
BAUD_6000000 = 6000000
BAUD_12000000 = 12000000
__slots__ = (
"debug",
"__txQueueDAs",
"__txQueueTelegrams",
"__allocUntil",
"__secPerFrame",
)
def __init__(self, debug=False, *args, **kwargs):
self.debug = debug
self.__close()
def _debugMsg(self, msg):
if self.debug:
print(self.PFX + str(msg))
def close(self):
"""Close the PHY device.
This method may be reimplemented in the PHY driver.
"""
self.__close()
def __close(self):
self.__txQueueDAs = deque()
self.__txQueueTelegrams = [None] * (0x7F + 1)
self.__allocUntil = monotonic_time()
self.__secPerFrame = 0.0
def sendData(self, telegramData, srd):
"""Send data to the physical line.
Reimplement this method in the PHY driver.
"""
raise NotImplementedError
def pollData(self, timeout):
"""Poll received data from the physical line.
timeout => timeout in seconds.
0.0 = no timeout, return immediately.
negative = unlimited.
Reimplement this method in the PHY driver.
"""
raise NotImplementedError
def poll(self, timeout=0.0):
"""timeout => timeout in seconds.
0.0 = no timeout, return immediately.
negative = unlimited.
"""
if self.__txQueueDAs:
self.__send()
return self.pollData(timeout)
def __send(self):
now = monotonic_time()
if self.__canAllocateBus(now):
da = self.__txQueueDAs.popleft()
telegram, srd, maxReplyLen = self.__txQueueTelegrams[da]
self.__txQueueTelegrams[da] = None
telegramData = telegram.getRawData()
self.__allocateBus(now, len(telegramData), maxReplyLen)
self.sendData(telegramData, srd)
def send(self, telegram, srd, maxReplyLen=-1):
if maxReplyLen < 0 or maxReplyLen > 255:
maxReplyLen = 255
da = telegram.da
if self.__txQueueTelegrams[da] is None:
self.__txQueueDAs.append(da)
self.__txQueueTelegrams[da] = (telegram, srd, maxReplyLen)
self.__send()
def setConfig(self, baudrate=BAUD_9600, *args, **kwargs):
"""Set the PHY configuration.
This method may be reimplemented in the PHY driver.
"""
symLen = 1.0 / baudrate
self.__secPerFrame = symLen * float(1 + 8 + 1 + 1)
def __canAllocateBus(self, now):
return now >= self.__allocUntil
def __allocateBus(self, now, nrSendOctets, nrReplyOctets):
secPerFrame = self.__secPerFrame
seconds = secPerFrame * nrSendOctets
if nrReplyOctets:
pass#TODO IFS
seconds += secPerFrame * nrReplyOctets
pass#TODO
self.__allocUntil = now + seconds
def releaseBus(self):
self.__allocUntil = monotonic_time()
if self.__txQueueDAs:
self.__send()
def clearTxQueueAddr(self, da):
"""Remove all TX queue entries for the given destination address.
"""
if da in self.__txQueueDAs:
self.__txQueueDAs.remove(da)
self.__txQueueTelegrams[da] = None
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