7220 Datasheet, PDF (193/303 Pages) Renesas Technology Corp – 8-BIT SINGLE-CHIP MICROCOMPUTER

APPLICATION
5.3 Usage example of ROM correction function (M37221M8/MA-XXXSP)
5.3.5 Notes on use
When using the ROM correction function, note the following.
qSpecify the first address (op code address) of each instruction as the ROM correction address.
qUse the RTS, RTI or JMP instruction (total of 3 bytes) to return from the correction program to the main
program.
qDo not set the same address to ROM correction addresses 1 and 2 (addresses 021716 to 021A16).
5-20
7220 Group User’s Manual