SH7055S Datasheet, PDF (825/1002 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7000 Series

Table 22.10 Software Protection
Item
Description
Protection by the
SCO bit
Protection by FKEY
Emulation
protection
Clearing the SCO bit in FCCS disables
downloading of the
programming/erasing program, thus
making the LSI enter a
programming/erasing-protected state.
Downloading and programming/erasing
are disabled unless the required key
code is written in FKEY. Different key
codes are used for downloading and for
programming/erasing.
Setting the RAMS bit in RAMER to 1
makes the LSI enter a
programming/erasing-protected state.
Function to be Protected
Download
Programming/
Erasure
O
O
O
O
O
O
22.6.3 Error Protection
Error protection is a mechanism for aborting programming or erasure when an error occurs, in the
form of the microcomputer getting out of control during programming/erasing of the flash
memory or operations that are not in accordance with the established procedures for
programming/erasing. Aborting programming or erasure in such cases prevents damage to the
flash memory due to excessive programming or erasing.
If the microcomputer malfunctions during programming/erasing of the flash memory, the FLER
bit in FCCS is set to 1 and the LSI enters the error protection state, thus aborting programming or
erasure.
The FLER bit is set to 1 in the following conditions:
• When the relevant block area of flash memory is read during programming/erasing (including
a vector read or an instruction fetch)
• When a SLEEP instruction (including software standby mode) is executed during
programming/erasing
Error protection is cancelled (FLER bit is cleared) only by a power-on reset or in hardware-
standby mode.
Note that the reset signal should only be released after providing a reset input over a period longer
than the normal 100 µs. Since high voltages are applied during programming/erasing of the flash
memory, some voltage may still remain even after the error protection state has been entered. For
Rev.2.0, 07/03, page 787 of 960