Well, now that sheds a bit of light onto the subject, or did I miss something previously??

Since I have a timer generating a timer tick, I would add some code here to implement a bit-banged transmit only uart as has previously been suggested. 1200 baud should be sufficient (~120 chars/sec) and normally you don't need to handshake (add delays where necessary) with the VFD device.

Set the timer to interrupt every 833uS (for 1200baud)
and each timer interrupt send out a bit (start,8 data bits,stop). Make sure the timer has a high interrupt priority otherwise other interrupts may cause some timing issues.

Faster baud rates require a faster timer tick, so be careful you don't get to a point where the cpu spends most of it's time servicing the timer tick.