topic Re: Flash security for LPC824 in LPCXpresso IDE

Flash security for LPC824

yannaingaye — Mon, 24 Apr 2017 04:36:53 GMT

I am using LPC824 OM13071 board. I want to make sure my firmware is secured from reading and copying by other parties. How can I program flash and protect it?

Re: Flash security for LPC824

lpcxpresso_supp — Mon, 24 Apr 2017 14:04:35 GMT

I suggest you look at the "Code Read Protection" functionality (CRP). For more details, check the LPC82x documentation, plus : https://community.nxp.com/message/630586

Regards,

LPCXpresso Support

Re: Flash security for LPC824

yannaingaye — Tue, 25 Apr 2017 04:19:33 GMT

I checked 'Edit project settings -> C/C++ Build -> Settings -> Tool Settings -> MCU Linker -> Managed Linker Script -> Enable Code Read Protection' is ticked.
In the crp.c file, I set " __CRP const unsigned int CRP_WORD = CRP_CRP2 ; "
Thenafter flash programming, I turned off the power, and on again to get power cycle .
When I tried debug again, nothing happened. I still can debug just like before.
Is there any other additional things to enable CRP?

Re: Flash security for LPC824

lpcxpresso_supp — Tue, 25 Apr 2017 10:36:21 GMT

Check the linker map file generated by the linker when it creates your image and make sure that the CRP_WORD is being located at the correct location.

You could also disassemble your image and make sure that the right value exists at that location too...

https://community.nxp.com/message/630600

Also, how exactly are you programming your image to flash?

Regards,

LPCXpresso Support

Re: Flash security for LPC824

yannaingaye — Tue, 06 Jun 2017 09:52:29 GMT

Thank you. It is OK now. The problem seems to be power cycle. It looks FTDI cable needs to be disconnected also, although I did not use power from it.

I used GUI flash programmer to program the flash. The details can be seen at

Cool-Emerald: Flash content protection for LPC824

I tested with LPCXpresso and it was ok.

Now, I change to MUCXpresso. When I checked the CRP_WORD at address 2fc, it appeared as 4321 8765 which is CRP3 instead of 0x87654321 CRP2 (as shown in the link above). I am afraid to test it because it will damage the board.

Why is it appear so? Is that just a change in order of appearance of the word while actual value is still CRP2?