Fujitsu MB90390 Series, Hardware Manual, Page: 577 / 740

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CHAPTER 26 ADDRESS MATCH DETECTION FUNCTION
●
When a program error occurs:
The main body of the patch program and program address are transferred to the MCU through the
connector (UART). The MCU writes the information to E
2
PROM.
●
Reset sequence
The MCU reads the value of E
2
PROM after reset. If the number of bytes of the patch program is not 0, the
main body of the patch program is read from E
2
PROM and written to RAM. The MCU then uses either
PADR0 or PADR1 to set the patch address and sets the compare enable bit. If the relocatable patch
program is required, the first address of the patched program can be written to the RAM area. In this case,
the INT9 routine accesses this user-defined RAM area and jumps to the patched program.
●
INT9 interrupt
The interrupt routine can know the address where the interrupt occurs by checking the value of the stack
program counter. The information that has been placed on the stack during the interrupt is discarded.
■
Example of Program Patch Processing
Figure 26.4-2 Example of Program Patch Processing
000000
H
RAM
ROM
FFFFFF
H
A b norm a l progr a m
S etting the progr a m a ddre ss detecting of re s et s e qu ence, exec u ting norm a l progr a m
Br a nch to the p a tch progr a m th a t i s exp a nded to RAM b y INT9 interr u ption from a ddre ss m a tch detection.
Exec u ting the p a tch progr a m b y b r a nching of INT9 oper a tion.
Exec u ting the norm a l progr a m th a t i s b r a nched b y the p a tch progr a m
E
2
PROM
Progr a m a ddre ss
detection s etting
(re s et s e qu ence)
Correction progr a m b yte n u m b er
Correction progr a m
Interr u pt gener a tion a ddre ss
Correction progr a m
Progr a m a ddre ss
detection regi s ter