Electronics America 8-Bit Single-Chip Microcontrollers User's Manual

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CHAPTER 25 ROM CORRECTION
25.4 ROM Correction Application
(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 CORAD0 or CORAD1 generates the
correction branch.
Figure 25-4. Storing Example to EEPROM (when one place is corrected)
Figure 25-5. Connecting Example with EEPROM (using 2-wire serial I/O mode)
V DD
V DD
V DD
PD78058, 78058Y
EEPROM
SCK0
SB1
P32
SCL
SDA
CS
CE
µ
RA78K/0
EEPROM
Source program
00
10
0D
02
9B
02
10
00H
01H
02H
FFH
CSEG AT 1000H
ADD A, #2
BR !1002H