Is dual Lockstep CPU same as dual Core processor?

Dino David

Intellectual 645 points

Other Parts Discussed in Thread: TMS570LS3137

I have a TMS570LS3137 Hercules Development Board which has dual cpu lockstep mechanism in it.

I wanted to know if I can disable this dual CPU lockstep and use it as a dual core cpu.

To be more precise, Can I execute different tasks on these cores parallelly?

over 10 years ago

0 Anthony F. Seely over 10 years ago

TI__Guru 69070 points

Dino,

No they stay locked. 2nd core always checks the 1st.

0 Martin Valencia over 10 years ago

Guru 15185 points

Anthony what he says is what differentiates the Hercules with other processors , Hercules family is a highly secure processor implemented.
two processors working as one and comparing answers, so you have a high confidence that your application will not fail

0 Dino David over 10 years ago in reply to Martin Valencia

Intellectual 645 points

I understand that this lockstep mechanism gives a level of confidence for saftey critical applications.

But I am confused now...Suppose if there is a change in the state of processors, what is next step ?

Does it raise a flag to interrupt the user about the discrepancies or does the second cpu will be in action on behalf of faulty one?

0 Anthony F. Seely over 10 years ago in reply to Dino David

TI__Guru 69070 points

Dino,

The configuration is called 1oo1D -- it's one channel plus a diagnostic.
So it can be used for fail-safe systems - where you can enter a safe state on an error.

See the intro to chapter 9 of www.ti.com/.../spnu499b.pdf for a good intro.

In general when the error occurs you don't know if it's a soft error caused by an event like radiation or if it's a hard error. So there is the possiblity to enter an ISR and run the BIST self test of the CPUs to check to see if it's a hard error. If it's just a soft error you may decide to restart or resume your application.

Key point here is that the 2nd CPU is always a diagnostic - it's never a 2nd channel that can act independently of the 1st CPU.

0 Dino David over 10 years ago in reply to Anthony F. Seely

Intellectual 645 points

Thanks Anthony for the clarifications

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Is dual Lockstep CPU same as dual Core processor?