R01UH0822EJ0100 Rev.1.00
Page 930 of 1041
Jul 31, 2019
RX13T Group
31. Flash Memory (FLASH)
31.5
Start-Up Program Protection
When rewriting the start-up program
by self-programming, if the rewrite operation is interrupted due to temporary
blackout, the start-up program may not be successfully programmed and the user program may not start properly.
This problem can be avoided by rewriting the start-up program without erasing the existing start-up program using the
start-up program protection. This function is available in products with a 32-Kbyte or larger ROM.
shows the Overview of the Start-Up Program Protection. In this figure, the default area indicates block 0 to
block 15, and the alternate area indicates block 16 to block 31.
Note 1. Program to perform operation to start the user program. It includes the fixed vector table.
Figure 31.3
Overview of the Start-Up Program Protection
FFFE 0000h
User program
Before rewriting
No program
(alternate area)
Original start-up
program
(default area)
FFFF 8000h
FFFF C000h
FFFF FFFFh
User program
New start-up
program
(alternate area)
Original start-up
program
(default area)
User program
New start-up
program
(alternate area)
Original start-up
program
(default area)
(1) Program a new start-up program in the alternate area. If the alternate area fails to be rewritten, the new start-up
program can be rewritten again after starting up using the default area, because the original start-up program is
in the default area.
(2) After the alternate area is successfully rewritten, the default area and the alternate area are switched using the
start-up area information program command. After that, the program in the alternate area starts after a reset.
(1)
(2)
Address