Kinetis MicrocontrollersのトピックRe: Please Clarify FSEC with Bootloader

Please Clarify FSEC with Bootloader

JHinkle — Tue, 01 Nov 2016 11:44:11 GMT

I want my KL17 and K64 devices to be secure yet be able to erase them if needed.

The FSEC is read and processed during reset which will make the FSEC associated with the bootloader take precedence.

Please clarify my understanding that the FSEC, FPROT, ect setting of the the application code have no bearing on how the device behaves.

Thanks.

Joe

Re: Please Clarify FSEC with Bootloader

mjbcswitzerland — Tue, 01 Nov 2016 19:18:41 GMT

Joe

Only the boot loader can set the Flash configuration parameters. The application never has any such.

It may be that the code "does have a table" but it will be located at an address that is not relevant to the reset and so its of no use.

Regards

Mark

Re: Please Clarify FSEC with Bootloader

JHinkle — Tue, 01 Nov 2016 21:16:33 GMT

Thanks for the confirmation Mark.

That's what I thought - just wanted to confirm.

Joe

Re: Please Clarify FSEC with Bootloader

kerryzhou — Wed, 02 Nov 2016 08:52:06 GMT

Hi Joe,

The most important data is the Flash configuration filed:

The flash configuration field is in the bootloader area, so you don't need to afraid that the APP will modify it.

Just make sure the 0X40D, 0X40C data is which you need, if you want to secure and enable the erase, don't protect the area which you want to erase, and set 0X40C data to 0x03.

Wish it helps you!

If you still have question, please contact me!

Have a great day,
Kerry

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Re: Please Clarify FSEC with Bootloader

JHinkle — Wed, 02 Nov 2016 10:42:26 GMT

Kerry:

0x40c set to 0 or 0xff would be no different correct?

You just don't want bits 0 and 1 to be b10 -- then you made a brick. The rest of the byte decides if the key is active, mass erase possible, NXP and read the device.

Joe

Re: Please Clarify FSEC with Bootloader

kerryzhou — Thu, 03 Nov 2016 02:25:50 GMT

Hi Joe,

The detail meaning of 0X40C data is in the FTFE_FSEC register:

So, the data 0x00 or 0XFF in address 0x40c is the same, if you want to secure the chip, just make sure SEC bit is not unsecured(0b10).

Wish it helps you!

If you still have question, please contact me!

Have a great day,
Kerry