Can you change the CRP register in LPC12XX when the program is running?

CRP Level 3 is the highest level supported by the LPC1100/LPC1300 devices. In sophisticated reverse engineering, an intellectual property thief may be able to learn proprietary information about a design by fully erasing and then programming the target device with custom test code and analyzing how the PCB behaves. This would then enable the thief to implement a counterfeit design without ever having read original object code. CRP Level 3 effectively disables ISP functionality1 and SWD, thus the device’s flash memory can no longer be modified. Should there be instances where hardware cannot be allowed to run unauthorized code, CRP Level 3 should be used. Be aware that there is no built-in recovery for designs once CRP Level 3 is enabled. The most simplistic way of implementing a custom recovery mechanism involves the “Re-Invoke ISP” IAP call.

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CAUTION: Although the example used in this application note was carefully tested, it is recommended that the user initially configure the device to a level lower than CRP3. Once the code is successfully tested, CRP3 can be used with confidence.

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