UPD78F0138 NEC, UPD78F0138 Datasheet - Page 429

• Manufacturer Part Number: UPD78F0138
• Description: (UPD78xxxx) 8-Bit Single-Chip Microcontrollers
• Manufacturer: NEC

26.4 ROM Correction Usage Example
as follows.
The example of ROM correction when the instruction at address 1000H “ADD A, #1” is changed to “ADD A, #2” is
(1) Branches to address F7FDH when the preset value 1000H in the correction address register matches the fetch
(2) Branches to any address (address F702H in this example) by setting the entire-space branch instruction (BR
(3) Returns to the internal ROM (internal flash memory) program after executing the substitute instruction ADD A,
address value after the main program is started.
!addr16) to address F7FDH with the main program.
#2.
EFFFH
0080H
0000H
1000H
1002H
internal flash memory
Internal ROM or
Program start
ADD A, #1
MOV B, A
Figure 26-4. ROM Correction Usage Example
CHAPTER 26 ROM CORRECTION
User’s Manual U16228EJ2V0UD
(1)
(3)
F7FDH
F7FFH
F400H
F702H
Internal expansion RAM
ADD A, #2
BR !1002H
BR !F702H
(2)
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