我正在尝试构建一个gui并从串口接收数据并在一个图中显示（使用matplotlib）。但是当我打开端口时，read（）失败了。我只是想不通为什么。请问有人给我一些建议吗？将不胜感激！ 这是我的代码的一部分： `
class PlotFigure(wx.Frame):
"""Matplotlib wxFrame with animation effect"""
def __init__(self):
wx.Frame.__init__(self, None, wx.ID_ANY, title="Figure for figures", size=(1200, 1200))
# Matplotlib Figure
self.fig = Figure((6, 4), 100)
# bind the Figure to the backend specific canvas
self.canvas = FigureCanvas(self, wx.ID_ANY, self.fig)
# add a subplot
self.ax = self.fig.add_subplot(111)
# limit the X and Y axes dimensions
self.ax.set_ylim([-180, 180])
self.ax.set_xlim([0, POINTS])
self.ax.set_autoscale_on(False)
self.ax.set_xticks([])
# we want a tick every 10 point on Y (101 is to have 10
self.ax.set_yticks(range(-180, 180, 50))
# disable autoscale, since we don't want the Axes to ad
# draw a grid (it will be only for Y)
self.ax.grid(True)
# generates first "empty" plots
self.user1=self.user2=self.user3 = [None] * POINTS
self.l_user1,=self.ax.plot(range(POINTS),self.user1,label='data1')
self.l_user2,=self.ax.plot(range(POINTS),self.user2,label='data2')
self.l_user3,=self.ax.plot(range(POINTS),self.user3,label='data3')
# add the legend
self.ax.legend(loc='upper center',
ncol=4,
prop=font_manager.FontProperties(size=10))
# force a draw on the canvas()
# trick to show the grid and the legend
self.canvas.draw()
# save the clean background - everything but the line
# is drawn and saved in the pixel buffer background
self.bg = self.canvas.copy_from_bbox(self.ax.bbox)
# bind events coming from timer with id = TIMER_ID
# to the onTimer callback function
wx.EVT_TIMER(self, TIMER_ID, self.onTimer)
#for serial
self.ser=serial.Serial('COM1', 115200)
#print self.ser
def onTimer(self, evt):
print 'onTimer....'
"""callback function for timer events"""
# restore the clean background, saved at the beginning
self.canvas.restore_region(self.bg)
# update the data
time.sleep(1)
self.ser.flushInput()
print 'before the read method....'
data=self.ser.read(12)
print 'after the read method... just cant reach here...'
t = struct.unpack('3f', data)
temp1 = t[0]
temp2 = t[1]
temp3 = t[2]
self.user1 = self.user1[1:] + [temp1]
print temp2
self.user2 = self.user2[1:] + [temp2]
self.user3 = self.user3[1:] + [temp3]
# update the plots
self.l_user1.set_ydata(self.user1)
self.l_user2.set_ydata(self.user2)
self.l_user3.set_ydata(self.user3)
# just draw the "animated" objects
self.ax.draw_artist(self.l_user1)
self.ax.draw_artist(self.l_user2)
self.ax.draw_artist(self.l_user3)# It is used to efficiently update Axes data (axis ticks, labels, etc are not updated)
self.canvas.blit(self.ax.bbox)
print 'onTimer ends'
def __del__(self):
self.ser.close()
t.Stop()
if __name__ == '__main__':
app = wx.PySimpleApp()
frame = PlotFigure()
t = wx.Timer(frame, TIMER_ID)
t.Start(1)
print 'new test'
frame.Show()
print 'after frame show '
app.MainLoop()
I wonder if it is the thread problem.so I do an another test:
Here is part of my code:
ser =serial.Serial(port='COM1',baudrate=115200,xonxoff=0)
def reading(ser):
flag = 1
print 'threading'
while True:
print ser.readable() #true
print 'before the read method.'
data = ser.read(12)
print 'after the read method... cant reach here.'
time.sleep(1)
if __name__ == '__main__':
threading.Thread(target=reading,args=(ser,)).start()
print 'main process1'
` 读取方法失败！
然后是另一个简单的测试，我摆脱了线程，它工作正常！ 这是我的代码部分： `
ser = serial.Serial('COM1', 115200)
num=0
try:
while True:
data = ser.read(12)
print num
time.sleep(1)
ser.flushInput()
finally:
ser.close()
`
答案 0 :(得分：0)
#
# The following is an example of an application I have running using the
# serial port. Although the baud is lower, it should not matter. This application
# will capture each byte and append them into a buffer before processing. All bytes
# are captured including non-printable characters. The terminator in my application
# is the RETURN character (0x0A) or the (0x0D) denoting end of line.
# I think your port is hung waiting on the full twelve (12) bytes that you are
# expecting on the read. The hang condition is because only a portion of
# the 12 bytes have occurred. I suggest you add a timeout value of 1 second
# to the serial read, then test for the length of what was read to validate
# what you think you just read. If zero, you have a serial cable or problem
# at the other end of the cable. If greater than zero, then the device is
# not sending what you think it should.
import serial
import string
import binascii
import threading
import thread
import fileinput
import datetime
import time
import sys
from configobj import ConfigObj
# Insert following code at top in the import area of your application
#
hdrFile = 'AppName.ini'
config = ConfigObj(hdrFile)
hdrVal = 'COM'
comport = int(config[hdrVal])
hdrBaud = 'Baudrate'
baudrate = config[hdrBaud]
print "Com Config = ",config
print "Com Port = ",comport
boolSerOnline = False
bool_IsALIVE = False # thread has active serial port
class myThread( threading.Thread ):
def __init__(self, intThreadID, strName, intCountVal ):
# --------------------------------------- Constructor
threading.Thread.__init__(self) # <<-- MUST be first in Init
self.threadID = intThreadID
self.threadName = strName
self.intStartCounter = intCountVal
def run(self):
# --------------------------------------- Tooltalk
# Thread to Listen to the RS-232 RX Port
# ------------------------------- TOOLTALK ()
# ------------------------------- THREAD
global bool_IsALIVE, boolThreadRun
#
#
inbuf = [] # Clear Buffer
buffer = "" # Clear Buffer
strFirstByte = ""
boolWriteCRLF = 0
#
print "\n*** Starting %s: %s" % ( self.threadName, time.ctime(time.time()))
print "\n"
#
bool_IsALIVE = False
#
# ----------------------------------- Start of Thread Loop
while ( boolThreadRun ):
# ----------------------------- THREAD is Running
try:
# ------------ Read 1 byte at a time in thread
# Note: reads all characters, Even non-printable characters
strByte = str(ser.read( 1 ))
#
intLength = len( strByte )
#
if ( intLength > 0 ):
bool_IsALIVE = True # Indicate connected
# Process byte
#
if (strFirstByte == ""):
boolWriteCRLF = 0
#
if ( strByte == '\r' ):
strByte = '' # Skip until we have first byte
elif ( strByte == '\n' ):
strByte = '' # Skip until we have first byte
elif ( strByte == '0' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte
boolWriteCRLF = 1
elif ( strByte == 'S' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte
boolWriteCRLF = 1
elif ( strByte == 'C' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte
boolWriteCRLF = 1
elif ( strByte == '*' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte # save first byte of string
boolWriteCRLF = 1
elif ( strByte == '>' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte # save first byte of string
boolWriteCRLF = 1
elif ( strByte == 'M' ):
inbuf = [] # Clear buffer first
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
strFirstByte = strByte # save first byte of string
boolWriteCRLF = 1
else:
pass
else:
inbuf.append( strByte ) # Add to inbuf
buffer = ''.join(inbuf) # join the two buffers
else:
# serial driver timed out producing No byte
# print "SKIP - NO BYTE (NO POWER?)"
pass
except:
bool_IsALIVE = False
print "[Tooltalk] Error reading Serial Port"
if __name__ == "__main__":
try:
# *** +++++++++++++ Notice the 1 second timeout ...
ser = serial.Serial(comport,baudrate,8,'N',1,timeout=1)
boolSerOnline = True
except:
print "[Main] Serial Port NOT Connected\n"
boolSerOnline = False
boolThreadRun = True # Flag indicating "Tooltalk" to Run
#
thread1 = myThread(1, "Tooltalk-1", 1) # Init Thread
thread1.start() # Start Tooltalk Thread