Mac上一个不错的读串口的库ORSSerialPort

https://github.com/armadsen/ORSSerialPort

当前版本不能一行一行读取串口数据，需要添加以下代码。

- (NSString *) readLine {
    char *bufptr;
    char buffer[1024];
    bzero(buffer, 1024);
    int nbytes;
    char inchar;
    
    int localPortFD = self.fileDescriptor;

    bufptr = buffer;
    while ((nbytes = read(localPortFD, &inchar, 1)) > 0)
    {
        if (inchar == '\n') break;
        if (inchar == '\r') break;
        *bufptr = inchar;
        ++bufptr;
    }
    *bufptr = '\0';
    return [NSString stringWithCString:buffer encoding:NSUTF8StringEncoding];
}

			// Data is available
//			char buf[1024];
//			long lengthRead = read(localPortFD, buf, sizeof(buf));
//			if (lengthRead>0)
//			{
//				NSData *readData = [NSData dataWithBytes:buf length:lengthRead];
//				if (readData != nil) [self receiveData:readData];
//			}
            
            NSString *line = [self readLine];
            if (line != nil) [self receiveData:[line dataUsingEncoding:NSUTF8StringEncoding]];