In a 78K0 device, the address range from 0000h to 7FFFh is allocated as the ROM area and the address range from 8000h to F7FFh is allocated as the external RAM area. However, the error message "ignored as outside of target memory area" is output when the assembler (or linker?) has reached the following code:
data2 dseg 8000h tmp: ds 2
Why can this method not be used to access an external memory area?
This error occurs because the existence of the external RAM has not been declared by a link directive.
Use an editor to insert the following memory directive into a link directive.
MEMORY RAMEX : (8000H,7800H)
In this memory directive, "RAMEX" is the name of the added external memory area (specify a name that is not already being used). Use the linker option -D to specify the file name of the link directive created in this way.
For the further description, see the sections 6.4 Link Directives and 6.6 Linker Options in CHAPTER 6 LINKER of the RA78K0 Assembler Package Operation User's Manual.