How correct use of Backdoor Key in FRDM-KL82Z board

[rysardsuboc]

I use official board and SDK libraries. I write my project in MDK.

I set the MCU in secure status and enabled backdoor key access.

When I use FLASH_SecurityBypass() function from library, function returned me FLASH Access Error status.

I entered the same backdoor key which is in FCCOB registers. For key entering I use terminal window.

The problem comes from FLASH_SecurityBypass() function where call flash_command_sequence() function. 

flash_command_sequence() function returned FLASH Access Error status.

[Robin_Shen]

Hi Rysard,

You can try to use the attached pflash.c and startup_MKL82Z7.s test on your FRDM-KL82Z board.

Using pflash exmaple in SDK_2.0_FRDM-KL82Z.

In startup_MKL82Z7.s file I have the following key entered:

/* Flash Configuration */

    .section .FlashConfig, "a"

    .long 0x01020304 /* //DES was 0xFFFFFFFF */

    .long 0x05060708 /* //DES was 0xFFFFFFFF */

    .long 0xFFFFFFFF

    .long 0xFFFFFFBC /* //DES enable BackDoorKey and lock flash=0xFFFFFFBC was 0xFFFFFFFE */

Using pflash.c I added test code:

uint8_t MyBackDoorKey[]={0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08};

//DES test works

The terminal output is:

The Count down gave me time to plug in the FRDM-KL82Z, let the VCOM enumerate, and then allow the terminal window to be open.

I loaded the example and modified it.  The two source files attached in ZIP file for reference.

Folder locations:

C:\SDK_2.0_FRDM-KL82Z\boards\frdmkl82z\driver_examples\flash\pflash.c

C:\SDK_2.0_FRDM-KL82Z\devices\MKL82Z7\iar\startup_MKL82Z7.s

Best Regards,

Robin

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