lpcmanager

Replaced RS485 RTS with GPIO. Added delay after transmit's write to cope with non blocking write, read received buffer in a loop until completion or timeout. NOTE : non realtime behavior of Linux UART driver may lead to write error since write may not finish befor receive mode is set again.

2014-12-11, Edouard Tisserant
4fff1de58ab4
Replaced RS485 RTS with GPIO. Added delay after transmit's write to cope with non blocking write, read received buffer in a loop until completion or timeout. NOTE : non realtime behavior of Linux UART driver may lead to write error since write may not finish befor receive mode is set again.
import serial
import exceptions
from threading import Lock
import time
class LPCProtoError(exceptions.Exception):
"""Exception class"""
def __init__(self, msg):
self.msg = msg
def __str__(self):
return "Exception in PLC protocol : " + str(self.msg)
class LPCProto:
def __init__(self, port, rate, timeout):
# serialize access lock
if BMZ_DBG:
# Debugging serial stuff
self._serialPort = serial.Serial( port, rate, timeout = timeout, writeTimeout = timeout )
class myser:
def readline(self_):
res = self._serialPort.readline()
print 'Recv :"', res, '"'
return res
def read(self_,cnt):
res = self._serialPort.read(cnt)
if len(res) > 16:
print "Recv :", map(hex,map(ord,res[:16])), "[...]"
else:
print "Recv :", map(hex,map(ord,res))
return res
def write(self_, string):
lstr=len(string)
if lstr > 16:
print "Send :", map(hex,map(ord,string[:16])), "[...]"
else:
print "Send :", map(hex,map(ord,string))
return self._serialPort.write(string)
# while len(string)>0:
# i = self._serialPort.write(string[:4096])
# print ".",
# string = string[i:]
# print
#return lstr
def flush(self_):
return self._serialPort.flush()
def close(self_):
self._serialPort.close()
self.serialPort = myser()
else:
# open serial port
self.serialPort = serial.Serial( port, rate, timeout = timeout )
# start with empty buffer
self.serialPort.flush()
def __del__(self):
if self.serialPort:
self.serialPort.close()
def close(self):
self.serialPort.close()
self.serialPort = None