Operations - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

21.4 Operations

21.4 Operations
When the program counter indicates the same address as the ROM Correction Address register, the INT9
instruction will be executed. By processing the INT9 interrupt service routine, the ROM correction function
can be achieved.
There are two address registers, in each containing a compare enable bit. When the address register and
the program counter are in agreement, and when the compare enable bit is at ' 1' , then the CPU will be
forced to execute INT9 instructions.
Note: When the address detection register and the program counter are in agreement, the
internal data bus content will be forced to be ' 01H', so interrupt INT9 will be executed.
Before changing the content of the address detect register, make sure the compare
enable bit is at ' 0'. If it is changed while the compare enable bit is at ' 1', there will
occur an error.
294 Chapter 21: ROM Correction Module MB90580 Series