Cant Write FSEC, SEC bits using FCA

[saurabhsaxena]

Hi,

I am trying to secure my internal flash on Kineris K81 MCU, using the Flash Configuration Area,

All the Bits I configuring as follows

__FlashConfig

DCD 0x9BABEAF8 ; [0x400 - 0x403] Backdoor Key Access
DCD 0x9BABEAF8 ; [0x404 - 0x407] Backdoor Key Access
DCD 0xFFFFFFFF ; [0x408 - 0x40B] Program Flash Protection Register
DCD 0xFFFFBCFF ; [0x40C - 0x40F] 0x40C: FSEC, 0x40D FOPT, 0x40E-F Reserved,
__FlashConfig_End

where 0x40C is the SEC field configured as 11, which means that the flash is secured.

But the problem is that when I try to read this configuration using the blhost utility I find the Flash Security in UNSECURED state, and the command 

blhost.exe -p COM3 read-memory 0x400 16 ./FCA.dat yields the following  

Can any one tell why the SEC setting are beings always set as 'E' 1110 where 10 is unsecure?

[kerryzhou · Accepted solution]

Hi Saurabh,

     If you just want to use the blhost to check the 0X40C data, and you find the 0X40C still 0XFE and not the 0XFF which you want to download.

    I don't know how you download the secured code to the chip? Some IDE or the debugger need to do the configuration, otherwise the secure area won't be updated.

   I highly suggest you generate the .hex file, then check the 0X40C at first, make sure the app.hex 0X40C is really 0XFF, then you can use the blhost download that app, then check it again.

   As I know, the IAR need to do the specific configuation, the KDS or MCUXpresso associate with the P&E debugger also may have problem, so, if you still want to use the debugger to download the code, I suggest you use the JLINK, when you select the chip, you must select the chip with partnumber<allow security>, then you can use the JLINK commander window, with JLINK commander: loadfile app.hex addr to download the code.

Please try it again in you side.

If you still have question about it, please kindly let me know.

Have a great day,
Kerry

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[saurabhsaxena]

Hi Kerry,

I am using IAR, the final HEX shows the FSEC's  SEC bit to be (11), But when I flash that I get (10),

Below is the snapshot, I using Jlink Commander to flash the MCU after doing a Erase chip.

I cant understand why its being forced into a unsecure state.

[kerryzhou]

Hi Saurabh,

     You are misunderstanding the FSEC secure function.

    Please check the K81 reference manual:

FSEC is just limit the debug access through the SWD/JTAG interface, it won't limit the ROM bootloader function.

 If you also don't want the ROM bootloader function work, you can can configure the BCA area, just disable the according ROM bootloader interface:

Wish it helps you!

Have a great day,
Kerry

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