Enable/disable servertickle / serverdown watchdog
        :param: enable: Set True to enable serverTickle
        :param: timeout_millis: millisecs until servertickle is triggered
        :param: stay_lit: Set True to keep current color of blink(1), False to turn off
        :param: start_pos: Sub-pattern start position in whole color pattern
        :param: end_pos: Sub-pattern end position in whole color pattern

def serverTickle(self, enable, timeout_millis=0, stay_lit=False, start_pos=0, end_pos=16):
        """Enable/disable servertickle / serverdown watchdog
        :param: enable: Set True to enable serverTickle
        :param: timeout_millis: millisecs until servertickle is triggered
        :param: stay_lit: Set True to keep current color of blink(1), False to turn off
        :param: start_pos: Sub-pattern start position in whole color pattern
        :param: end_pos: Sub-pattern end position in whole color pattern
        """
        if ( self.dev == None ): return ''
        en = int(enable == True)
        timeout_time = int(timeout_millis/10)
        th = (timeout_time & 0xff00) >>8
        tl = timeout_time & 0x00ff
        st = int(stay_lit == True)
        buf = [REPORT_ID, ord('D'), en, th, tl, st, start_pos, end_pos, 0]
        self.write(buf)