MPC5744 FCCU Initialization Issue

[ahmedsoubky]

Hi, 

What conditions can lead to the occurrence of FCCU NCF[12] ( Core redundancy mismatch: D-MEM array interface out of lockstep ) ? 

According to AN5259: "The root cause can be a permanent fault or a transient fault (either in the safety lake or in the original lake) that propagated to any outputs of the lake." 

Currently, when we change time in which FCCU is initialized. FCCU goes into ALARM state because of NCF[12] and goes back again into NORMAL state.

Could it be a fault in Lockstep Core and not in Core 0 or might it be the cores aren't completely synchronized during initialization. In other words, what could be the reasons behind this FCCU fault ? 

Also, from your experience, in a standard AUTOSAR environment initialization sequence: 

The problem basically happens when we move FCCU init to any Init Block other than Init Block III. 

What is your recommendation when the FCCU initialization should take place ? 

Thanks, 

Ahmed 

[petervlna]

Hi,

NCF[12] is caused by RCCU fault which represent lock-step error on D-MEM controller which is replicated in safety lake.

Usually I do FCCU init in main as first called function.

But in safety systems it should be done when device is ready to execute safety tasks.

After Power on Reset, when second core is activated during reset phase (via DCF record) then RCCU faults can occur.

Clear the faults and if the RCCU fault is also present after other then POReset then you must analyze it.

If the fault is present only After POR then it is caused by delayed activation of core and makes no sense to analyze this fault.

Peter