Python：线程在通过串行端口接收0f字节后关闭

Question

我正在制作与收银机进行通信的程序，当我在上面测试打印机时（打印数字从0到100），我注意到每次我得到这个字节（0f为十六进制）并且我的线程阻塞或关闭。我的项目由2个程序组成，一个用于与收银机和tcp进行通信，另一个用于tcp端口（稍后将添加DB） 所以这是4线程程序：

#!/usr/bin/env python

import thread

import crcmod
import Queue
import serial
import socket
import time
#portovi
TCP_IP = '127.0.0.1'
TCP_PORT=5007

v =0
lockSerial = thread.allocate_lock()
lockTcp = thread.allocate_lock()
lockPrn = thread.allocate_lock()
serialBuff = []
tcpBuff = []
prnBuff = []
prnReady=1
stx = chr(0x02)
etx = chr(0x03)
ack = chr(0x06)
nack = chr(0x15)
prnCmd = ('PB','PD','PF','P'+chr(0xc2))
crc8 = crcmod.mkCrcFun(0x131, 0x00)

ser = serial.Serial( 0 , baudrate=19200, bytesize=8, parity='N', stopbits=2, timeout=None, xonxoff=0, rtscts=0, writeTimeout=None, dsrdtr=None)
ser.open()
ser.sendBreak()
sl = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sl.bind((TCP_IP, TCP_PORT))
sl.listen(1)

connl, addr = sl.accept()

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((TCP_IP, TCP_PORT+1))
s.listen(1)

conn, addr = s.accept()
def toHex(s):
    lst = []
    for ch in s:
        hv = hex(ord(ch)).replace('0x', '')
        if len(hv) == 1:
            hv = '0'+hv
        lst.append(hv)

    return reduce(lambda x,y:x+y, lst)
#hex2bit
def hex2bit(string):    
    novi = bin(int(string, 16))[2:]
    if len(novi)<8:
        pom=8-len(novi)
        while pom!=0:
            novi = str(0)+novi
            pom=pom-1
    return novi
def serialRecv():
    messageSerRec = ''
    global prnReady
    while 1:

        byte = ser.read()#shuts down here
        if not toHex(byte)=='0f':#even if I change it it shuts down
            if byte == ack:
                print 'ACK'
            elif byte == nack:
                print 'NACK'
            else:
                if byte == stx:
                    messageSerRec = ''
                elif byte == etx:
                    messageSerRecFin = messageSerRec[:-2]
                    chSum = int ('0x%s'%messageSerRec[-2:],0)
                    if chSum == crc8(messageSerRecFin):
                        lockSerial.acquire()
                        serialBuff.append(messageSerRecFin)
                        print "Serial Recv: ", messageSerRecFin
                        lockSerial.release()
                        ser.write(ack)
                        prnReady = 1
                    else: ser.write(nack)
                else: messageSerRec = messageSerRec+byte
        time.sleep(0.01)

def tcpSend(): 
    while 1:
        if serialBuff:
            lockSerial.acquire()
            conn.send(serialBuff[0])
            print "Tcp Send: ", serialBuff[0]
            serialBuff.remove(serialBuff[0])
            lockSerial.release()
    time.sleep(0.01)

def tcpRecv():
    pom=""    
    while 1:
        messageTcpRec = connl.recv(25)
        i=0
        if len(messageTcpRec)>0:
            while i<len(messageTcpRec):
                if not messageTcpRec[i]==';':
                    pom=pom+messageTcpRec[i]
                else:
                    prnBuff.append(pom)
                    pom=""
                i=i+1
            print prnBuff
        #if not messageTcpRec=="":
        #    print "Tcp Recv: ", messageTcpRec
        #    if messageTcpRec[:2] in prnCmd:
        #        lockPrn.acquire()
        #        prnBuff.append(messageTcpRec)
        #        lockPrn.release()
        #    elif tcpBuff:
        #        lockTcp.acquire()
        #        tcpBuff.append(messageTcpRec)
        #        lockTcp.release()
    time.sleep(0.01)

def serialSend():
    global prnReady
    while 1:
        #print "prnRdy=", prnReady
        if tcpBuff:
            print "tcpBuff:", tcpBuff[0]
            lockTcp.acquire()
            ser.write(stx+tcpBuff[0]+hex(crc8(tcpBuff[0]))[-2:].upper()+etx)
            print "Serial Send: ", (tcpBuff[0])
            tcpBuff.remove(tcpBuff[0])
            lockTcp.release()
        if prnBuff:
            if prnReady == 1:
                lockPrn.acquire()
                ser.write(stx+prnBuff[0]+hex(crc8(prnBuff[0]))[-2:].upper()+etx)
                print "Serial Send(prn): ", (prnBuff[0])
                prnBuff.remove(prnBuff[0])
                lockPrn.release()
                prnReady = 0
        time.sleep(0.01)

thread.start_new_thread(serialRecv,())
thread.start_new_thread(tcpSend,())
thread.start_new_thread(tcpRecv,())
thread.start_new_thread(serialSend,())
while 1:pass
s.close()

因此线程serialRecv在收到该字节时关闭 我一直试图在最后2-3天内完成这项工作，但无法找到解决方案。