4 rom correction application – NEC PD78058FY(A) User 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 correction address register 0, 1

(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)

RA78K/0

EEPROM

Source program

00

10

0D

02

9B

02

10

00H

01H

02H

FFH

CSEG AT 1000H

ADD A, #2

BR !1002H

V

DD

V

DD

V

DD

PD78058F, 78058FY

EEPROM

SCK0

SB1

P32

SCL

SDA

CS

CE

µ

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