SH7080 Datasheet, PDF (1298/1644 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperH™ RISC engine Family

Section 23 Flash Memory
Initial
Bit
Bit Name Value
R/W
31 to 0 UA31 to Undefined R/W
UA0
Description
User Branch Destination Address
When the user branch is not required, address 0
(H'00000000) must be set.
The user branch destination must be an area other than
the flash memory, an area other than the RAM area in
which on-chip program has been transferred, or the
external bus space.
Note that the CPU must not branch to an area without
the execution code and get out of control. The on-chip
program download area and stack area must not be
overwritten. If CPU runaway occurs or the download
area or stack area is overwritten, the value of flash
memory cannot be guaranteed.
The download of the on-chip program, initialization,
initiation of the programming/erasing program must not
be executed in the processing of the user branch
destination. Programming or erasing cannot be
guaranteed when returning from the user branch
destination. The program data which has already been
prepared must not be programmed.
Store general registers R8 to R15. General registers R0
to R7 are available without storing them.
Moreover, the programming/erasing interface registers
must not be written to or RAM emulation mode must not
be entered in the processing of the user branch
destination.
After the processing of the user branch has ended, the
programming/erasing program must be returned to by
using the RTS instruction.
For the execution intervals of the user branch
processing, see note 2 (User branch processing
intervals) in section 23.8.3, Other Notes.
Rev. 3.00 May 17, 2007 Page 1240 of 1582
REJ09B0181-0300