Application Example Of Rom Correction; Fig. 21.2 System Structure Example - Fujitsu MB90420/5 (A) Series Hardware Manual

MB90420/5 (A) SERIES F

21.2 Application Example of ROM Correction

The ROM correction function is enabled by externally providing an EEPROM and by storing information on
corrections and a patch program in the EEPROM.
EEPROM, the CPU sets addresses requiring corrections in the ROM correction module and transfers the
patch program to RAM. The processing can be transferred to the patch program by executing the INT9
instruction after address match detection.
n System structure
MCU
2
F MC-16LX
n EEPROM memory map
address: content
0000 : byte count of the patch program No. 0 (ROM not corrected at 0)
H
0001 : bit 7 to bit 0 of program address No. 0
H
0002 : bit 15 to bit 8 of program address No. 0
H
0003 : bit 24 to bit 16 of program address No. 0
H
0004 : byte count of the patch program No. 1 (ROM not corrected at 0)
H
0005 : bit 7 to bit 0 of program address No. 1
H
0006 : bit 15 to bit 8 of program address No. 1
H
0007 : bit 24 to bit 16 of program address No. 1
H
0010 : patch program No. 0/1 body
H
n Initial condition
Data empty (all 0)
2
MC-16LX FAMILY 16-BIT MICROCONTROLLERS HARDWARE MANUAL
EEPROM
Pull up resistor
SIN

Fig. 21.2 System Structure Example

Based on the correction information stored in the
Connector (UART)
21-6