OK, Thanks for the tip. My plan was to display text on a LCD driver. Now it is difficult to type 8 bit equivalent for each alphabet. So, I was planning to define each alphabet (upper case and lower case) as constant in a text file and then somehow refer this file in the program to type out words and lines of words. Is it possible? If so/ if not what can be the possible way.
You can think about ROM tables generated at FPGA compile time. FPGA design tools have different options to load binary or hex files during compilation, unfortunately there's no standard VHDL command for this purpose.
Or load character tables and text strings to FPGA internal RAM through an interface at run time.