SH7058 Datasheet, PDF (924/1130 Pages) Renesas Technology Corp – Renesas SuperHTM RISC engine

Table 23.10 Software Protection
Item
Protection by the
SCO bit
Protection by FKEY
Emulation
protection
Description
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
23.6.3 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 bank 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. 3.0, 09/04, page 883 of 1086