Is SSD1963 gpio compatible with 5v?
Appears to be NO. (VDD= 3.3V
(SEE PAGE 76)
With a courage and concern, i tried the SSD1963 GPIO directly to arduino pins. at it works!
They are likely to work. i plugged many 3.3V TFT shields to 5V, both power and I/O's accidentally and so far have yet to burn one.
Having said this, thats all it was: Accidentally plugging in for a short period of time. Consistent operation at such levels is likely to cause damage at some point. Ask yourself if this is something you can afford and go from there.
I'm not worried about the I/O pins because they can usually tolerate 5V input but the power is another thing altogether.
You may want to consider level shifters.
Can you post a photo or link for your display ?