timeout = None, then the read call will block until the requested number of bytes are there. If you want to wait until data arrives, just do a read(1) with timeout None. If you want to check data without blocking, do a read(1) with timeout zero, and check if it returns any data#Modified code from main loop:
s = serial.Serial(5)
#Modified code from thread reading the serial port
while 1:
tdata = s.read() # Wait forever for anything
time.sleep(1) # Sleep (or inWaiting() doesn't give the correct value)
data_left = s.inWaiting() # Get the number of characters ready to be read
tdata += s.read(data_left) # Do the read and combine it with the first character
... #Rest of the code
you should set the baud rate in your serial.Serial(...) command, otherwise the camera might not recognize whatever command you're sending there. something along the lines of:
cam = serial.Serial("/dev/ttyUSB0", baudrate=9600)
Also, you may specify the timeout as a parameter, with the possible values:
timeout = None: wait forever
timeout = 0: non-blocking mode (return immediately on read)
timeout = x: set timeout to x seconds#!/usr/bin/python
import serial, time
#initialization and open the port
#possible timeout values:
# 1. None: wait forever, block call
# 2. 0: non-blocking mode, return immediately
# 3. x, x is bigger than 0, float allowed, timeout block call
ser = serial.Serial()
#ser.port = "/dev/ttyUSB0"
ser.port = "/dev/COM5"
#ser.port = "/dev/ttyS2"
ser.baudrate = 9600
ser.bytesize = serial.EIGHTBITS #number of bits per bytes
ser.parity = serial.PARITY_NONE #set parity check: no parity
ser.stopbits = serial.STOPBITS_ONE #number of stop bits
#ser.timeout = None #block read
ser.timeout = 1 #non-block read
#ser.timeout = 2 #timeout block read
ser.xonxoff = False #disable software flow control
ser.rtscts = False #disable hardware (RTS/CTS) flow control
ser.dsrdtr = False #disable hardware (DSR/DTR) flow control
ser.writeTimeout = 2 #timeout for write
try:
ser.open()
except Exception, e:
print "error open serial port: " + str(e)
exit()
if ser.isOpen():
try:
ser.flushInput() #flush input buffer, discarding all its contents
ser.flushOutput()#flush output buffer, aborting current output
#and discard all that is in buffer
#write data
ser.write("AT+CSQ")
print("write data: AT+CSQ")
time.sleep(0.5) #give the serial port sometime to receive the data
numOfLines = 0
while True:
response = ser.readline()
print("read data: " + response)
numOfLines = numOfLines + 1
if (numOfLines >= 5):
break
ser.close()
except Exception, e1:
print "error communicating...: " + str(e1)
else:
print "cannot open serial port "import serial
port = serial.Serial("/dev/ttyAMA0", baudrate=115200, timeout=3.0)
while True:
port.write("\r\nSay something:")
rcv = port.read(10)
port.write("\r\nYou sent:" + repr(rcv))
import serial.tools.list_ports
list = serial.tools.list_ports.comports()
connected = []
for element in list:
connected.append(element.device)
print("Connected COM ports: " + str(connected))
# deu pau por permissao denied
# sudo adduser MyUser dialout
# sudo chmod a+rw /dev/ttyUSB0
ser = serial.Serial(
port='/dev/ttyUSB0',\
baudrate=9600,\
parity=serial.PARITY_NONE,\
stopbits=serial.STOPBITS_ONE,\
bytesize=serial.EIGHTBITS,\
timeout=0, \
xonxoff=False, \
dsrdtr=False, \
rtscts=False)
print "esta aberto:", ser.is_open
ser.write("\r\nDiga algo:")
rcv = ser.readline()
ser.write("\r\nVoce mandou:" + repr(rcv))
