Got the Front panel working with a MC6800 FPGA CPU. FPGA Build is here. Same button/LED arrangement. 

• RUN/Halt Pushbutton - Stop CPU and enable Front Panel control of memory.
• SETADR button/LED - Allows an address to be entered.
• SETDAT button/LED - Allows data to be entered to load into SRAM.
• INCADR - If SETDAT is active, writes to SRAM then increments address. If SETDAT is not active examines the next memory location.

Works great!