Running Arduino Uno UART at 526500 Baud

Hello Each,

So I’ve been playing around for a few days now trying to get my project working.

In a nutshell, all it needs to do is “print” a few characters over the UART to control another device which can not be modified.

The issue is, I need this to be done at 526,500 baud. Looking at the AVR Baud Rate calculator, I can expect issues using the Uno with it’s 16Mhz crystal - and when a basic programme was constructed to test the concept, I was seeing a baud rate of 500,000, according to my trusty logic probe.

Now, I’ve tried simply swapping the crystal out for an 18Mhz version (which looks like it may work according to the AVR Baud calculator), which has now meant that the Arduino software / Windows / Mac no longer recognises the USB device.

Can anyone give me any pointers?

Many thanks!

Now, I've tried simply swapping the crystal out for an 18Mhz version

And rewritten the bootloader?

Would that prevent it from being recognised by the computer at all?