INTERNAL MEMORY
6.8 Internal Flash Memory Protect Function
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6.8 Internal Flash Memory Protect Function
The internal flash memory has the following four types of protect functions to prevent it from being inadvertently
rewritten or illegally copied, programmed or erased.
(1) Flash memory protect ID
When using a tool to program/erase the internal flash memory such as a general-purpose programmer or emu-
lator, the ID entered by a tool and the ID stored in the internal flash memory are collated. Unless the correct ID
is entered, no programming/erase operations can be performed. (For some tools, tool execution is enabled after
erasing the entire flash memory area, and the internal flash memory becomes accessible for write.)
(2) Protection by FP pin
The internal flash memory is protected in hardware against programming/erase operation by pulling the FP
(Flash Protect) pin low. Furthermore, because the FP pin level can be known by reading the Flash Mode Regis-
ter (FMOD)’s FPMOD (external FP pin status) bit in the flash write/erase program, the internal flash memory can
also be protected in software. For systems that do not require protection by setting external pins, the FP pin may
be fixed high to simplify the operation to program/erase the internal flash memory.
(3) Protection by FENTRY bit
Flash E/W enable mode cannot be entered into unless the Flash Control Register 1 (FCNT1)’s FENTRY (flash
mode entry) bit is set to "1". To set the FENTRY bit to "1", write "0" and then "1" in succession while the FP pin
is high.
(4) Protection by a lock bit
Any block of internal flash memory can be protected by setting the lock bit provided for it to "0". That memory
block is disabled against programming/erase operation.
32180 Group User’s Manual (Rev.1.0)
6-38
RENESAS [ RENESAS TECHNOLOGY CORP ]
