在 Tkinter 文本框中显示从串行端口读取的数据时,发出处理数据
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【中文标题】在 Tkinter 文本框中显示从串行端口读取的数据时,发出处理数据【英文标题】:Issue processing data read from serial port, when displaying it in a Tkinter textbox 【发布时间】:2019-11-04 10:03:34 【问题描述】:所以我正在从串行连接读取(并使用 tkinter 文本框显示)数据,但我无法按我的意愿处理返回的数据,以便运行我的测试。更简单地说,即使显示了machine response = 0x1
,我也无法从全局serBuffer
中读取它。
在将其显示给textbox
之前,我将从测试function
中读取,然后检查响应是否在string
中,但现在我将读取的数据(字符串)传递给全局变量并然后尝试阅读它,它似乎不起作用,除非我从readserial
中删除serBuffer = ""
。但这会导致一个新问题。当我按下按钮发送命令时,它发送它,但仅在我第二次按下它之后才收到响应,并且每次之后。因此,如果我运行一次测试,我会得到一个Fail
,但之后我每次都会通过。
带有期望响应的图片(test function
不读取 0x1 并且总是返回 FAIL)
带有 non-desired 响应的图片(仅在第二次按下它之后才收到响应,并且每次之后都收到响应。因此,如果我运行一次测试,我会得到一个失败,但之后我每次都通过)。
import tkinter as tk
import serial
from serial import *
serialPort = "COM3"
baudRate = 115200
ser = Serial(serialPort, baudRate, timeout=0, writeTimeout=0) #ensure non-blocking
#make a TkInter Window
mainWindow = tk.Tk()
mainWindow.wm_title("Reading Serial")
mainWindow.geometry('1650x1000+500+100')
scrollbar = tk.Scrollbar(mainWindow)
scrollbar.pack(side=tk.RIGHT, fill=tk.Y)
log = tk.Text ( mainWindow, width=60, height=60, takefocus=0)
log.pack()
log.config(yscrollcommand=scrollbar.set)
scrollbar.config(command=log.yview)
#make our own buffer
#useful for parsing commands
#Serial.readline seems unreliable at times too
serBuffer = ""
ser.write(b'\r\n')
def readSerial():
while True:
c = (ser.read().decode('utf-8', 'ignore')) # attempt to read a character from Serial
# was anything read?
if len(c) == 0:
break
# get the buffer from outside of this function
global serBuffer
# check if character is a delimeter
if c == '\r':
serBuffer += "\n" # don't want returns. chuck it
if c == '\n':
serBuffer += "\n" # add the newline to the buffer
# add the line to the TOP of the log
log.insert('1.1', serBuffer)
serBuffer = "" # empty the buffer
else:
serBuffer += c # add to the buffer
mainWindow.after(100, readSerial) # check serial again soon
def test():
command = b" test command \r\n"
ser.write(command)
global serBuffer
time.sleep(0.5)
if "0x1" in serBuffer:
print('PASS')
return 'PASS'
else:
print('FAIL')
return 'FAIL'
button = tk.Button(mainWindow, text="Pone Test", font=40, bg='#b1c62d', command=test)
button.place(relx=0.8, rely=0, relwidth=0.1, relheight=0.05)
# after initializing serial, an arduino may need a bit of time to reset
mainWindow.after(100, readSerial)
mainWindow.mainloop()
【问题讨论】:
你在if "0x1" in serBuffer:
之前做serBuffer = "" # empty the buffer
。分为local read_buffer
和global last_command
。
感谢您的回答!你能编辑我的代码来理解你的意思吗?
【参考方案1】:
评论:但仅在第二次按下它之后才收到响应,并且每次按下它之后。因此,如果我运行一次测试,我会失败,但之后每次都会通过
将第一个超时从100
提高到500
或更多。
# after initializing serial, an arduino may need a bit of time to reset
mainWindow.after(100, self.readSerial)
要找出第一个响应的延迟,请尝试以下操作:
注意:您必须在不运行
def readSerial
的情况下执行此操作,以防止同时清空in buffer
"
command = b" test command \r\n"
self.ser.write(command)
delay = 0.0
# wait until you get `.in_waiting` data.
while not self.ser.in_waiting:
time.sleep(0.1)
delay += 0.1
print('.', end='')
if delay >= 10:
print('BREAK after no in_waiting'.format(int(delay * 10)))
break
print('Delay:, in_waiting:'.format(delay, self.ser.in_waiting))
以下内容对我有用。
注意:我使用
OOP
语法。
last_command
serBuffer = ""
last_command = None
将准备好的read_buffer
复制到last_command
,只为空read_buffer
def readSerial(self):
while True:
c = (self.ser.read().decode('utf-8', 'ignore')) # attempt to read a character from Serial
# was anything read?
if len(c) == 0:
break
# get the buffer from outside of this function
global serBuffer
# check if character is a delimeter
if c == '\r':
serBuffer += "\n" # don't want returns. chuck it
if c == '\n':
serBuffer += "\n" # add the newline to the buffer
global last_command
last_command = serBuffer
# add the line to the TOP of the log
# log.insert('1.1', last_command)
print('readSerial.last_command:""'.format(bytes(last_command, 'utf-8')))
serBuffer = "" # empty the buffer
else:
serBuffer += c # add to the buffer
print('readSerial:""'.format(bytes(serBuffer, 'utf-8')))
self.after(100, self.readSerial) # check serial again soon
做test()
def test(self, write=True):
print('test(write=)'.format(write))
if write:
command = b" test command \r\n"
self.ser.write(command)
self.after(500, self.test, False)
elif last_command is not None:
print('last_command:'.format(bytes(last_command, 'utf-8')))
if "0x1" in last_command:
print('PASS')
else:
print('FAIL')
else:
# ATTENTION: This could lead to a infinit loop
# self.after(500, self.test, False)
pass
输出:
test(write=True) readSerial:"b' '" readSerial:"b' t'" readSerial:"b' te'" readSerial:"b' tes'" readSerial:"b' test'" readSerial:"b' test '" readSerial:"b' test c'" readSerial:"b' test co'" readSerial:"b' test com'" readSerial:"b' test comm'" readSerial:"b' test comma'" readSerial:"b' test comman'" readSerial:"b' test command'" readSerial:"b' test command '" readSerial:"b' test command \n\r'" readSerial.last_command:"b' test command \n\r\n'" test(write=False) last_command:b' test command \n\r\n' FAIL
注意:我得到
FAIL
,因为last_command
中没有0x1
,因为我使用PORT = 'loop://'
,它与所写的内容相呼应!
【讨论】:
我收到一个错误:TypeError: argument of type 'NoneType' is not iterable
那么你的def readSerial():
没有到达last_command = serBuffer
。这意味着你没有收到任何东西,或者你要早点去做if "0x1" in last_command:
我会添加一些延迟,看看它是否解决了问题,谢谢你的帮助!
好吧显然增加延迟并没有使它起作用,我也尝试了ser.send_break
,但这也不起作用。我很确定我正在接收数据,但当我没有将它显示到文本框时我已经完成了它。唯一的区别是我正在阅读 Pycharm
@Deezer:更新我的答案,TEST 关于第一次延迟。【参考方案2】:
我做了一些更改,检查一下。
def readSerial():
while True:
c = (ser.read(1).decode('utf-8', 'ignore')) from Serial
if len(c) == 0:
break
global serBuffer
if c == '\r':
serBuffer += ""
if c == '\n':
serBuffer += "\n"
log.insert(tk.END, serBuffer)
log.see(tk.END)
log.update_idletasks()
serBuffer = ""
else:
serBuffer += c
mainWindow.after(500, readSerial)
【讨论】:
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