update xmodem checksum test
update xmodem checksum test

akuhtz/serial-communication-manager,RishiGupta12/serial-communication-manager,RishiGupta12/SerialPundit,RishiGupta12/SerialPundit,akuhtz/serial-communication-manager,RishiGupta12/serial-communication-manager,RishiGupta12/SerialPundit,akuhtz/serial-communication-manager,RishiGupta12/serial-communication-manager,RishiGupta12/SerialPundit,akuhtz/serial-communication-manager