Mega 2560 Project board 16mhz

Hi, I have included a Mega 2560 on a pcb design for my project and all is good apart from serial comm. I am communicated with other devices on the serial line and there is no synchronisation.I altered to baud rate on my project to be twice as fast as the the receiving devices and that did work although i dont want that long term.

The speed of my mega is set o 1mhz as default programming using Atmel studio. I have the 8mhz internal clock running but I want to use 16mhz external oscillator. Has anybody done this or know the best process/ practices please? Fir instance, which LOW.SUT_CKSEL to select?
Thanks

Im answering my one question here:) I plugged the avrisp to the genuine uno and read the fuse setting , easy :wink:


2021-05-20T23:00:00Z

Take a look at the fuse settings used in the IDE for the Mega 2560 board for external 16 MHz xtal:

mega.menu.cpu.atmega2560.bootloader.extended_fuses=0xFD
mega.menu.cpu.atmega2560.bootloader.high_fuses=0xD8
mega.bootloader.low_fuses=0xFF
mega.bootloader.unlock_bits=0x3F
mega.bootloader.lock_bits=0x0F