Do UART TX use interrupts?

I would like to use one of the extra serial output on a Mega to drive a serial backpack on an LCD display.

I know that receiving on the uart causes interrupts, I would just be sending. I have sent debugging info to the serial monitor and never heard any disturbance (it is a synthesizer, which uses interrupts, and parallel display or other interrupts stepping on my ISR causes all kinds of pops and crackles) so that leads me to believe it should be fine.

I just want to be sure before i go and buy a serial backpack and then find out its not going to work without disturbing the sound. I am hoping it is similar to writing to a port.

any insight would be greatly appreciated.

As of arduino-0017, the answer is "no" (I haven't upgraded to 0018 yet).

There's been some talk about implementing it (possibly as a contributed add-on), but I don't think it's been done.

Thanks, I will go ahead and try it then.