I've got two Raspberry Pi's sending data to each other using the Serial Port and a pair of XRF Radio's. Generally they work fine and the full program loops multiple times but every once in a while one of them stops the program with a error along the lines of:
File "BaseListener.py, line 56, in <module>
recieved=serialport.read()
File "/usr/lib/python2.7/dist-packages.serial/serialposix.py", line 465, in read raise SerialException('Device reports readiness to read but returned no data (device disconnected?)')
serial.serialutil.SerialException: device reports readiness to read but returned no data (device disconnected?)
My Code is:
import sys
import serial
import time
import datetime
date = datetime.date.today()
strdate = str(date)
serialport=serial.Serial("/dev/ttyAMA0", 9600, timeout=0.25)
command=''
loop=0
recieving=False
recieving2=False
format = "%Y-%m-%d %H:%M:%S"
while True:
while (recieving==False):
loop = 0
command=''
while (loop<30):
recieved = serialport.read()
command = command + recieved
loop = loop+1
if "DR" in command:
print"DR Recieved"
serialport.write("BSAKAKBS")
recieving=True
while (recieving ==True):
loop = 0
command=''
while (loop<30):
recieved = serialport.read()
command = command + recieved
loop = loop+1
sensorid = command[0:2]
print ("Command: "+command)
print ("SensorID: "+sensorid)
graintemp = command[2:6]
print "GrainTemp Recieved"
serialport.write("BS"+graintemp+"BS")
print (str(graintemp))
loop = 0
command=''
while (loop<30):
recieved = serialport.read()
command = command + recieved
loop = loop+1
if sensorid in command:
if "AK" in command:
print "GrainTemp AK recieved"
serialport.write("BSAKAKBS")
recieving2=True
while (recieving2==True):
loop=0
command=''
while (loop<30):
recieved = serialport.read()
command = command + recieved
loop = loop+1
print ("Command: "+command)
airtemp = command[2:6]
print "AirTemp Signal Recieved"
serialport.write("BS"+airtemp+"BS")
print ("AirTemp: "+str(airtemp))
loop = 0
command=''
while (loop<30):
recieved = serialport.read()
command = command + recieved
loop = loop+1
if sensorid in command:
if "AK" in command:
print ("AK command: ")
print "AirTemp AK Recieved"
serialport.write("BSAKAKBS")
#File Storage
today = datetime.datetime.today()
fulltime = today.strftime(format)
strtime = str(fulltime)
graindata = fulltime + ' ' + graintemp +'\n'
airdata = fulltime + ' ' + airtemp +'\n'
file = open(sensorid+"Graindata.dat", "a")
file.write(graindata)
file.close
file = open(sensorid+"Airdata.dat", "a")
file.write(airdata)
file.close
recieving=False
recieving2=False
loop=0
command=''
graindata=''
airdata=''
graintemp=0
airtemp=0
print "Files stored. Restarting"
else:
print ("IC Command: ")
print "Airtemp IC Recieved"
serialport.write("BSICICBS")
loop = 0
command=''
else:
print "Airtemp ID IC Recieved"
serialport.write("BSICICBS")
loop = 0
command=''
else:
serialport.write("BSICICBS")
print "Graintemp IC Recieved"
loop = 0
command=''
else:
serialport.write("BSICICBS")
print "Graintemp ID IC Recieved"
loop = 0
command=''
The code on the other Pi is similar (I can provide if needed).
From what I've found online, it's some issue to do with trying to read the serial port but it being empty. I've seen suggestions to use a try and catch exception but im not sure that will help (or know how to do that really). I need the code to run continuously without any interference at all from a user. If the serial port is empty then the AK and IC loops should pick it up the same as an incorrect transmission so I just need it to pass the empty value on. Is there any way to do this?