repos_gamma/Python/baseSerail.py

# -*- coding: UTF-8 -*-
import serial
import time
import binascii

'''
描述：串口同步基类
'''


class BaseSerial():
    # 构造函数
    def __init__(self):
        self.exception = None
        self.ser = serial.Serial()

    '''
    打开串口
    '''
    def open(self, port, baudrate=115200, bytesize=8, parity=serial.PARITY_NONE, stopbits=1, timeout=3, writeTimeout=0.5):
        if type(port) == type(0):
            self.ser.port = "COM" + str(port)
        else:
            self.ser.port = port
        # 波特率;
        self.ser.baudrate = baudrate
        # 数据位;
        self.ser.bytesize = bytesize
        # 校验码;
        self.ser.parity = parity  # PARITY_NONE=0
        # 停止位;
        self.ser.stopbits = stopbits
        # 串口读超时值
        self.ser.timeout = timeout
        # 串口写超时值
        self.ser.write_timeout = writeTimeout
        try:
            self.ser.open()
            # 返回结果;
            return self.ser.is_open
        except Exception as e:
            self.exception = e
            print('打开串口异常', str(e))
            return False


    '''
    重新打开串口
    '''
    def reOpen(self):
        self.exception = None
        self.ser.close()
        try:
            self.ser.open()
            # 返回结果;
            return self.ser.is_open
        except Exception as e:
            self.exception = e
            return False

    '''关闭串口'''
    def close(self):
        self.ser.close()


    '''
    描述：写串口
    '''

    def write(self, cmd: bytearray):
        try:
            self.exception = None
            writelen = self.ser.write(cmd)
            # flush等待写入完成;
            self.ser.flush()
            print("writehex:" + str(binascii.b2a_hex(cmd)) + " writelen=" + str(writelen))
            return True if writelen == len(cmd) else False
        except Exception as e:
            self.exception = e
            print('写串口异常', str(e))
            return False

    '''
    描述：读取串口数据;
    返回：返回16进制字符串;
    补充：ser.in_waiting 实际是缓冲区里的数据长度,也就是要读的长度;
    '''    

    def read(self, size=0):
        try:
            time.sleep(0.1) # 必备的等待-机器响应;
            self.exception = None
            # 先读取1个,如果超时表示通讯失败;
            bys = self.ser.read(1)
            for i in range(0, 3):
                while self.ser.in_waiting > 0:
                    d = self.ser.read(1)
                    bys = bys + d
                # 每当缓冲区为0,等10ms,循环3次确保机器响应完全;
                time.sleep(0.01)
            
            # 再判断是否读取到指定大小(size!=0);
            if bys.__len__() < size:
                time.sleep(0.1) # 等待0.1秒让机器响应;
                if self.ser.in_waiting > 0:
                    d = self.ser.read(self.ser.in_waiting)
                    bys = bys + d
            print("readhex:" + str(binascii.hexlify(bys)) + " readlen=" + str(bys.__len__()))
            return bys
        except Exception as e:
            self.exception = e
            print('读串口异常', str(e))
            return None
    
    def read2(self, size=0):
        try:
            self.exception = None
            time.sleep(0.01)
            # 先读取1个,如果超时表示通讯失败;
            bys = self.ser.read(1)
            while self.ser.in_waiting > 0:
                d = self.ser.read(1)
                bys = bys + d

            # 再sleep一会,机器响应可能过慢,导致有字节遗漏;
            time.sleep(0.015)
            while self.ser.in_waiting > 0:
                d = self.ser.read(1)
                bys = bys + d
           
            # 再判断是否读取到指定大小(size!=0);
            if bys.__len__() < size:
                time.sleep(0.1) # 等待0.1秒让机器响应;
                if self.ser.in_waiting > 0:
                    d = self.ser.read(self.ser.in_waiting)
                    bys = bys + d
            print("readhex:" + str(binascii.hexlify(bys)) + " readlen=" + str(bys.__len__()))
            return bys
        except Exception as e:
            self.exception = e
            print('读串口异常', str(e))
            return None


if __name__ == "__main__":
   pass