Im thinking about using the eeprom memory on the microchip, the 16F648A
as 256k of eeprom, which should be plenty for small displays and it is easier to erase and write using a PicKit2. It will also be easier to move the eeprom data to RAM when the microchip starts up, this allowing us to read the data faster
Am I right in saying that you have to erase the 27C512
eprom with a UV light every time you want to load it with more display data?
Unfortunately it is only 256bytes of eeprom not Kbytes
as for the eprom's yes you are right you do have to expose them to UV light for about 20mins to erase them.
But EEPROM's however, you can erase them with the same programmer that you program them with so they are basically instant.