S32K144 - detect partition settings and change partitioning settings at runtime

[andy63]

Hello all,

I'm working with a S32K144 device, no RTOS, no SDK are used.
The device memory is partitioned for EEPROM usage as shown in reference manual (page 864) and in workshop document - AMF-AUT-T3822 Writing CSEc Security Software on S32K MCU_rev2.pdf - tables / sample code (page 27, 29).

For some historical reasons we have devices in the field - fully potted - with invalid settings. The CSEc Key size field is set to 0x00 instead of 0x03. The firmware of these devices must be updated via field bus interface. I do not have access to the SWD programmer interface.

So I am faced with two questions which must be solved in the new firmware:

• How to determine which CSEc key size value is actually set in this controller?
• Once I have determined the partitioning (CSEc key size value) is wrong (zero value), how can I change the partitioning from a running application?

The register SIM->FCFG1 provides the information about EEPROM data set size and FlexNVM partition code.

But for CSEc key size value I'm missing an equivalent register.

Kind regards,

Andreas

[andy63]

Hello Daniel,

thanks for your reply. 

That's not quite what I was hoping for, but now I have to find a way to deal with it.

Regards,

Andreas

[danielmartynek · Accepted solution]

Hi Andreas,

There is no register that would show the size of the space allocated for the CSEc keys.

But I think you can tell which MCU has been partitioned from FlexRAM.

Because, for example, if the allocated CSEc space is 512B, the space 0x14000E00-0x14000FFF will not be accessible.

It should generate a bus fault on a read access.

The partitioning can be removed either by Mass Erase or by CMD_DB_CHAL and CMD_DBG_AUTH provided the MCU is partitioned for CSEc.

I'm afraid you will need to mass erase the MCU that are partitioned for EEPROM but not for CSEc.

Regards,

Daniel