32186 datasheet(196/1032 Pages) RENESAS

196 / 1032 page

INTERNAL MEMORY

6-54

32185/32186 Group Hardware Manual

Rev.1.10 REJ09B0235-0110 May 15, 07

6.10 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

emulator, the ID entered by a tool and the ID stored in the internal flash memory are collated. Unless the correct

ID is entered, the internal flash memory cannot be read out, programmed nor erased. (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 "L." For systems that do not require rewriting flash memory or systems in which flash

reprogramming is prohibited as in the case of automotive applications, make sure the FP pin is fixed "L" except

when programming or erasing the internal flash memory. Furthermore, because the FP pin level can be known

by reading the Flash Mode Register (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 protec-

tion by setting external pins, the FP pin may be fixed "H" to simplify the operation to program/erase the internal

flash memory. However, to prevent the flash memory from being inadvertently rewritten by an erratic operation

in software, use the protection by a lock bit described in (4) below.

When programming/erasing via JTAG, the flash memory can be programmed or erased regardless of the pin

state because the FP pin is controlled internally within the chip.

(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 "H."

(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.

6.10 Internal Flash Memory Protect Function

32186 Datasheet(PDF) 196 Page - Renesas Technology Corp