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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 pyprofibus.util import *
class PhyError(ProfibusError):
"""PHY exception.
"""
class CpPhy(object):
"""PROFIBUS CP PHYsical layer base class.
"""
# 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
def __init__(self, debug = False):
self.debug = debug
self.__close()
def close(self):
"""Close the PHY device.
This method may be reimplemented in the PHY driver.
"""
self.__close()
def __close(self):
self.__txQueue = []
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 = no timeout, return immediately.
negative = unlimited.
Reimplement this method in the PHY driver.
"""
raise NotImplementedError
def poll(self, timeout = 0):
"""timeout => timeout in seconds.
0 = no timeout, return immediately.
negative = unlimited.
"""
if self.__txQueue:
self.__send()
return self.pollData(timeout)
def __send(self):
telegramData, srd, maxReplyLen = self.__txQueue[0]
if self.__allocateBus(len(telegramData), maxReplyLen):
self.__txQueue.pop(0)
self.sendData(telegramData, srd)
def send(self, telegramData, srd, maxReplyLen = -1):
if maxReplyLen < 0 or maxReplyLen > 255:
maxReplyLen = 255
self.__txQueue.append((telegramData, srd, maxReplyLen))
self.__send()
def setConfig(self, baudrate = BAUD_9600):
"""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 __allocateBus(self, nrSendOctets, nrReplyOctets):
now = monotonic_time()
if now < self.__allocUntil:
return False
secPerFrame = self.__secPerFrame
seconds = secPerFrame * nrSendOctets
if nrReplyOctets:
pass#TODO IFS
seconds += secPerFrame * nrReplyOctets
pass#TODO
self.__allocUntil = now + seconds
return True
def releaseBus(self):
self.__allocUntil = monotonic_time()
if self.__txQueue:
self.__send()
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