Question about running on-line BIST on MPC5777C EVB

youngseolee · ‎01-02-2022

I am checking the on-line BIST function in the MPC5777C EVB by referring to the MPC5777C on-line BIST sample code posted to the community.

While checking the on-line BIST function, it was confirmed that the result of the on-line BIST differs depending on whether the nexus interface is connected to the MPC5777C EVB.

From what I have checked, if the nexus interface is connected to the MPC5777C (the debugger is not running), no fail is recorded in the STCU2 error register, but If the nexus interface is not connected to the MPC5777C, fail is recorded in the WDTOSW bit of the STCU2 error register.

Also, the on-line BIST result is different depending on the reset condition by the main power switch (SW5 of the mother card) and the reset condition by the RESET switch (SW2 of the Daugter card).

The following is the display of the on-line BIST execution result in teraterm.

Result of connecting NEXUS interface to MPC5777C and running on-line BIST
(The on-line BIST result is the same for the reset condition by SW5 of the mother card and the reset condition by SW2 of the Daugter card.)
----------------------------------------------------------------------------
-Start BIST!!
RSR: 0x80008090 (STCURS is '0')
LBSSW: 0x00000000
LBESW: 0x00000000
MBSLSW: 0x00000000
MBELSW: 0x00000000
ERR_STAT: 0x00000000

FCCU_NCF_S0 is 0x00000000
FCCU_NCF_S1 is 0x00000000

-Check BIST Result!!
RSR: 00048090 (STCURS is '1')
LBSSW: 0000003F
LBESW: 0000003F
MBSLSW: FFFFFFFF
MBELSW: FFFFFFFF
ERR_STAT: 00000000

FCCU_NCF_S0 is 0x00000000
FCCU_NCF_S1 is 0x00000000
----------------------------------------------------------------------------

Result of running online BIST without connecting NEXUS interface to MPC5777C (reset by SW5 on motherboard card)
----------------------------------------------------------------------------
- Check BIST Result!!
RSR: 00048090 (STCURS is '1')
LBSSW: 00000000
LBESW: 00000000
MBSLSW: 00000000
MBELSW: 00000000
ERR_STAT: 00000008

FCCU_NCF_S0 is 0x00000000
FCCU_NCF_S1 is 0x00000000
----------------------------------------------------------------------------

Result of running online BIST without connecting NEXUS interface to MPC5777C (reset by SW2 on daugter card)
----------------------------------------------------------------------------
-Start BIST!!
RSR: 40008090 (STCURS is '0')
LBSSW: 00000000
LBESW: 00000000
MBSLSW: 00000000
MBELSW: 00000000
ERR_STAT: 00000008

FCCU_NCF_S0 is 0x00000000
FCCU_NCF_S1 is 0x00000000

-Check BIST Result!!
RSR: 00048090 (STCURS is '1')
LBSSW: 0000003F
LBESW: 0000003F
MBSLSW: FFFFFFFF
MBELSW: FFFFFFFF
ERR_STAT: 00000008

FCCU_NCF_S0 is 0x00000000
FCCU_NCF_S1 is 0x00000000
----------------------------------------------------------------------------

In relation to the above results, we would like to know the answers to the following three questions.

1. Can the connection status of the nexus interface affect the results of BIST?

2. The generated error is 'WDTO (Off-line watchdog time-out)'. Can we ignore the WDTO error that occurred during on-line BIST execution?

3. Why is 'STCURS' recognized as '1' from the start of booting if the power is turned off/on(using SW5 on mother card) while the NEXUS interface is not connected to the MPC5777C?

Thanks

petervlna · ‎01-13-2022

Hello,

I was looking deeper into this and the solution is quite simple.

The error from WDTO is from offline selftest, which is executed if you do power on reset.

So, if you want to run only online self test, you have to bypass offline one or run offline one correctly.

To bypass it is is enough program these DCFs:

STCU key: D3FEA98B 00080008

STCU key: 2C015674 00080008

Bypass: 00000400 00080000

Best regards,

Peter

petervlna · ‎01-05-2022

Hello,

I'd like to know if the nexus connector connection status can affect the on-line BIST results, but there doesn't seem to be anything like that anywhere.

as far as I know, yes as the LBIST is testing SIU unit, where the status of pins are reflected.

Also, I'm curious as to why 'STCURS' is recognized as '1' when booting starts if the power is cycled

When test is executed at its end the reset is triggered to load the correct reset values to register instead of test patterns, but the test is skipped as it was already executed.

Best regards,

Peter

youngseolee · ‎01-05-2022

A case similar to the problem I mentioned is posted at the URL below.

https://community.nxp.com/t5/MPC5xxx/About-STCU2-configuration-on-MPC5777C-cut-3N45H/m-p/942881

Do you know how it was solved?

petervlna · ‎01-10-2022

Hello,

I have run the tests and I see also WDTO set without debugger connected.

I have tasked designer to explain this behavior.

I will update it here when I have clarified this issue.

Best regards,

Peter

petervlna · ‎01-05-2022

Hello,

looking into your tests I see the only reason why the test fails was your Watchdog settings.

Watchdog needs to be hand tuned according to your application HW. Slightly increase its value and see if the test past.

Usually you want to look at the point where the watchdog just pass and add an offset of 10%.

Best regards,

Peter

youngseolee · ‎01-05-2022

Hello,

I'd like to know if the nexus connector connection status can affect the on-line BIST results, but there doesn't seem to be anything like that anywhere.

Also, I'm curious as to why 'STCURS' is recognized as '1' when booting starts if the power is cycled (using SW5 on the motherboard) while the NEXUS interface is not connected to the MPC5777C.

Can you answer my question?