How to Configure Time period for FCCU Eout signal

[bdharma96]

Hi,

   I'm working with MPC5775E MCU along with a PMIC. The Error Signal Monitor in PMIC (in PWM mode) will detect an error condition on the ERROR/WDI pin if one of the events that follows occurs:

• The high-pulse duration on the ERROR/WDI pin is greater than the threshold value that is
programmed by the SAFETY_ERR_ PWM_HMAX register.
• The high-pulse duration on the ERROR pin is less than the threshold value that is programmed by the
SAFETY_ERR_ PWM_HMIN register.
• The low-pulse duration on the ERROR/WDI pin exceeds the threshold value that is programmed by the
SAFETY_ERR_ PWM_LMAX register.
• The low-pulse duration on the ERROR pin is less than threshold value that is programmed by the
SAFETY_ERR_ PWM_LMIN register.

The programmable time range for each of these four threshold values is between 15 μs and 3.84 ms, with
15-μs resolution steps.

In s32 design studio I can add the fccu component from component library and can choose between the different modes

but how to set the time period for the signals(between 15us and 3.84ms) being generated by FCCU ?

Please help with this

[davidtosenovjan]

Hi, I believe this is application specific.

Safety manual says:

"The sum of the MPC5775E/B fault indication time and system fault reaction time should be less than the FTTI of the functional safety goal."

[bdharma96]

Hi,
   We will be connecting MPC5775E's EOUT signal pin to the PMIC ERROR/WDI pin which will be configured with the above mentioned time period range(15 μs and 3.84 ms).

The PMIC is supposed to monitor the EOUT signals from MPC5775E within this specified time period continuously.
In case of MCU fault, the time period of EOUT signals may get changed (not within the specified range) which will be detected by the PMIC as MCU fault.

My query is How to set that time period for EOUT signal, If it is application specific can you please provide the time period range of MPC5775E's MCU in different modes and also the use of pre-scalar.

please provide details of registers to be configured to set EOUT signals.  

[bdharma96]

I found a macro FEATURE_FCCU_FOP_SUPPORT  which is defined in the file  MPC5775E_features.h in the location C:\NXP\S32DS_Power_v2.1\S32DS\software\S32_SDK_S32PA_RTM_3.0.0\platform\devices\MPC5775E\include

Also found the below snippet of code ,

#if !defined(FEATURE_FCCU_FOP_SUPPORT)
/* Base on prescaler Value can be calculated (value/64)|(value%64) Max Allow Value is 127 */
FCCU_SetFaultOutputPrescalerExtension(base, ((param->prescaler >> 0x6U) == 0U) ? false : true); /*divide by 64*/
FCCU_SetFaultOutputPrescaler(base, (param->prescaler & 0x3FU)); /*modulo by 64*/
#endif /* FEATURE_FCCU_FOP_SUPPORT */ 

Can you please explain if FOP SUPPORT is defined , then why the FCCU_SetFaultOutputPrescalerExtension & FCCU_SetFaultOutputPrescaler function calls are commented.

If I change the above code as below will this feature work in MPC5775E.

#if defined(FEATURE_FCCU_FOP_SUPPORT)
/* Base on prescaler Value can be calculated (value/64)|(value%64) Max Allow Value is 127 */
FCCU_SetFaultOutputPrescalerExtension(base, ((param->prescaler >> 0x6U) == 0U) ? false : true); /*divide by 64*/
FCCU_SetFaultOutputPrescaler(base, (param->prescaler & 0x3FU)); /*modulo by 64*/
#endif /* FEATURE_FCCU_FOP_SUPPORT */ 

Kindly revert back ASAP.

[davidtosenovjan]

FTTI time is given by application according given ASIL class.

Please consult with your company safety team/expert or certification company.

[bdharma96]

Hi,

   Can you explain your point more detailed. Actually our question was regarding FEATURE_FCCU_FOP_SUPPORT,

is this available in MPC5775E ?

[davidtosenovjan]

I see. I am sorry I misunderstand your question. You wants to know whether frequency of EOUT error signal may be changed. No it is fixed frequency of 61Hz as FOP, FOPE bits are read-only on this device (and the is no DCF client for modification its default value), so EOUT frequency cannot be changed.