flash security (MKM14Z64ACHH5)

[zunda1958]

Hello, I have a question about flash security in kinetis KM1.

Please tell me about flash security in kinetis KM1.

If I enable the BACKDOOR function, can I say the following?
1)The FROM read function returns illegal data.
2)FROM code fetching is possible.
3)FROM read from the user program is possible.
4)In other words, the execution of user programs is not affected.
5)Read from the SWD port returns an illegal code.
6)SWD debugging is not affected.

Thank you in advance.

[xiangjun_rong]

Hi,

when you write the Flash Configuration Area and configure the flash in security mode, after Reset, the SWD port is blocked, you can not read code/data from flash or internal RAM, in this way, the code/data in flash is protected, this is the target of the security mode.

But in security mode, the flash code can be fetched and executed without any effect.

In security mode, just the SWD port is blocked. But the BACKDOOR function opens a door for the security mode. Because the backdoor keys are saved in Flash Configuration Area, for example, you want to press a button to unblock the SWD port, in the ISR of button, you can execute the Verify Backdoor Access key, if the keys are matched, the SWD can be unblocked temporarily, you can read flash data from SWD until the chip is reset.

Pls refer to section 45.4.10.10 Verify Backdoor Access Key Command

Hope it can help you

BR

XiangJun Rong