Reset
Read the 00h of E
YES
0000h (E2PROM)=0
Read the Address
0001h~0003h (E2PROM)
PADR0 (MCU)
Read the Corrected Program
0010h~0090h (E2PROM)
000400h~000480h (MCU)
Enable compare
MOV PACSR, #02h
Normal Program Execution
PC=PADR0
MB90580 Series
2
PROM
NO
MOV
MOV
NO
YES
INT9
FFFF
H
0090
H
Corrected Program
0010
H
Lower Program Address: 00
0003
H
Middle Program Address: 00
0002
H
Upper Program Address: FF
0001
H
Size of Corrected
Program in Byte: 80
0000
H
Figure 21.5c ROM Correction Processing Flow Diagram
INT9
To Corrected Program
JMP 000400h
Corrected Program Execution
000400h~000480h
End of Corrected Program
JMP FF0050h
ROM
2
E
PROM
RAM
Chapter 21: ROM Correction Module
21.5 Application Example
FFFFFF
H
FF0050
H
Erroneous Program
FF0000
H
FE0000
H
001100
H
Stack Area
RAM Area
000480
H
Corrected Program
000400
H
RAM/Register Area
000100
H
I/O Area
000000
H
297