CHAPTER 25 ROM CORRECTION
User’s Manual U16899EJ2V0UD
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25.5 ROM Correction Application
How to apply the example shown in 25.4 is described below.
(1) Store the correction address and instruction after correction (patch program) to nonvolatile memory (such as
EEPROM
TM
) outside the microcontroller.
When two places should be corrected, store the branch destination judgment program as well. The branch
destination judgment program checks which one of the addresses set to correction address registers 0 and 1
(CORAD0 or CORAD1) generates the correction branch.
Figure 25-5. Example of Storing to EEPROM (When One Place Is Corrected)
RA78K0
EEPROM
Source Program
00
10
0D
02
9B
02
10
00H
01H
02H
FFH
CSEG AT 0000H
DW #1000H
ADD A, #2
BR !1002H