This is what Seial.print(HEX) is displaying anyway.
It would display data differently if you used uint8_t as the type of Send_buf.
Post a picture showing how that device is connected to the UNO and/or the Mega.
This is what Seial.print(HEX) is displaying anyway.
It would display data differently if you used uint8_t as the type of Send_buf.
Post a picture showing how that device is connected to the UNO and/or the Mega.