[ABANDONED] Secure chip on STM32L486 MCU

HenryL · Jan 25th 2016, 10:36pm

Hi,

I need to run secure chip on the STM32L486 MCU, but the command is not available in current release of J-Flash v5.10h. Is there a plan to update J-Flash to allow option bytes for Cortex-M4 devices? When would that be approximately?

Thanks,

Henry

SEGGER - Niklas · Jan 26th 2016, 6:20pm

Hi Henry,

The "Secure Chip" is only available for some older derivatives.
On most current ones there is no easy "secure chip".
Usually the devices (including the STM32L4) support multiple security levels so "secure chip" would be ambiguous.

It is recommended to perform the enable of the desired security level via the exit steps in J-Flash.
For more info see J-Flash manual -> Device Specifics -> ST "7.6.4 STM32F4 series devices - option byte programming"

which gives an idea how to do this.

Best regards,
Niklas

HenryL · Feb 5th 2016, 2:56am

Hi Niklas,

I tried option byte programming. When execute 'auto', J-Flash goes through erase, program and verify before running the exit script.
In this case, how do I avoid it overwriting the data already in the flash? In a way, how do I set the project that the exit script is executed, but my programmed data not being changed? This 'option byte programming' would be the last step in my program where data file downloaded, some tests executed, then read protect the chip.

Thanks,
Henry

SEGGER - Erik · Feb 11th 2016, 9:46am

Hi Henry,

Can you please explain what you actual mean with "programmed data changed"?
Does the entire flash is empty? Does certain areas have different values?

Basically, the exit steps do not change your programmed data, as long as they do not include steps to change them...
The procedure is as follows
InitSteps() --> Prepare device (e.g. remove protection, configure clocks, configure pins etc...)
Erase() --> Erase device
Program() --> Data file
Verify() --> Verify programmed data
ExitSteps() --> Activate security
If you just activate the security via the exit steps, no programmed data will be changed.
If the programmed data change, your exit steps include not only the "activate security" sequence but also a sequence to change the programmed data.
If you provide us with your J-Flash project file, we can have a look at it.

Best regards
Erik

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