import serial

ser = serial.Serial(

    port='/dev/ttyAMA0',
    baudrate=9600,
    parity=serial.PARITY_NONE,
    stopbits=serial.STOPBITS_ONE,
    bytesize=serial.EIGHTBITS,
    timeout=1
)
ser.reset_output_buffer()

print('Serial connected')

def nxRead(value):
    #first i need to send a 'command' (for example 'sendme X.value'
    command = 'sendme X.value'
    ser.write(command.encode('latin-1'))
    ser.write(chr(255).encode('latin-1')) # 0xFF
    ser.write(chr(255).encode('latin-1')) # 0xFF
    ser.write(chr(255).encode('latin-1')) # 0xFF

    #by now the device should have understood my request and will send me a reply byte by byte, finishing with 0XFF 0XFF 0XFF 

    reply = [] 
    count =0
    t3FF = False # the termination has not stopped

    while t3FF == False:
       r = ser.read().decode('latin-1)
       c = ord(r)
       reply.append(c)
         
           if c == 0xff:
               count = count + 1
               if count == 3:
                   t3FF = True
                   return
           else:
               count = 0
    return s