Detecting S32K358 Lockstep Pairs

[darknite2023]

Hi. I am working on S32K3X8EVB-Q289 devkit and trying to figure out the right way to determine which cores are configured to be S32K358's lockstep core?

I dumped DCM_GPR.DCMROF19 register and got: 0x60000000 which indicates:

• - DCM DONE
• - LOCKSTEP EN on M7_Core0 and M7_Core1

To verify, I then dumped MSCM's registers

• - Core 0, Cfg2 @ 0x40260034
  • Got back 0x09080000 which indicates DTCM and ITCM sizes correspond to lockstep.
•  Core 1, Cfg2 @ 0x4026054
  • Got back 0x08070000 which can be ignored since DCMROF19 indicates Lockstep is enabled.
•  Core 2, Cfg2 @ 0x4026074
  • Got back 0x09080000 which indicates DTCM and ITCM sizes correspond to lockstep.

I expected Core 2, Cfg2 register to contain 0x08070000 but instead I see a value that indicates lockstep configuration. So, does this mean Core0 and Core2 are the pairs that make up the lockstep core an if so, this does not line up with what DCM_GPR.DCMROF19 contents as described in the S32K3XX Ref Manual.

I would be grateful if someone could either point out the flaw in my understanding as per the reference manual or provide the foolproof way of detecting which cores are in lockstep configuration.

Thanks in advance.

[davidtosenovjan · Accepted solution]

Actually it is basically correct, DTCM2 really has doubled ITCM/DTCM size, but it does not indicate lockstep/decoupled mode. Only memory size. I will report this discrepancy.

[darknite2023]

Thanks for quick response and clarifying that.

Fixing the documentation will definitely help avoid any such confusion. I wonder if there are similar misleading pieces of information the reference manual?

Thanks again.

[davidtosenovjan]

Unfortunately, I don't know, but there are always some errors in every documentation.

[davidtosenovjan]

I will test it on HW tomorrow, letting you know.

In the meanwhile, could you please specify MCU part number that is installed on the EVB? All lines please

[darknite2023]

Thanks for the quick response.

The  devkit consists of:
- SoC: NXP S32K358HVS, 0P14E, CTZE2233A
- Other labeling: SCH-54870 Rev B2, 700-54870 Rev X2

Regards.

[davidtosenovjan]

I can confirm it behaves same way on my side as well. Let me further investigate.

[darknite2023]

Sounds good. Thanks for confirming so quickly.