Beyond issues registered by earlier responder - might the requirement for some fast, volatile memory - receive some consideration?
Most all of these more basic MCUs don't easily/efficiently attach to/accommodate external RAM. A newer, more expensive device does however (129 device iirc) and may prove more suitable for your development efforts. After you've realized some success - methods to employ less capable MCUs here - may have a greater chance of success...
As w/most things in engineering - trade-offs/balance become normal/customary. The "specs" - absent here - prevent little beyond the general approach provided here - by now two responders...