SH7125_08 Datasheet, PDF (644/774 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 17 Flash Memory
(2) Interrupts during programming/erasing
Though an interrupt processing can be executed at realtime during programming/erasing of the
downloaded on-chip program, the following limitations and notes are applied.
1. When flash memory is being programmed or erased, the user MAT cannot be accessed.
Prepare the interrupt vector table and interrupt processing routine in on-chip RAM. Make
sure the flash memory being programmed or erased is not accessed by the interrupt
processing routine. If flash memory is read, the read values are not guaranteed. If the
relevant bank in flash memory that is being programmed or erased is accessed, the error
protection state is entered, and programming or erasing is aborted. If a bank other than the
relevant bank is accessed, the error protection state is not entered but the read values are
not guaranteed.
2. Do not rewrite the program data specified by the FMPDR parameter. If new program data
is to provided by the interrupt processing, temporarily save the new program data in
another area. After confirming the completion of programming, save the new program data
in the area specified by FMPDR or change the setting in FMPDR to indicated the other
area in which the new program data was temporarily saved.
3. Make sure the interrupt processing routine does not rewrite the contents of the flash-
memory related registers or data in the downloaded on-chip program area. During the
interrupt processing, do not simultaneously perform download of the on-chip program by
an SCO request or programming/erasing.
4. At the beginning of the interrupt processing routine, save the CPU register contents. Before
returning from the interrupt processing, write the saved contents in the CPU registers again.
5. When a transition is made to sleep mode or software standby mode in the interrupt
processing routine, the error protection state is entered and programming/erasing is
aborted.
If a transition is made to the reset state, the reset signal should only be released after
providing a reset input over a period longer than the normal 100 µs to reduce the damage to
flash memory.
Rev. 4.00 Jul. 25, 2008 Page 624 of 750
REJ09B0243-0400