Hello,
I am working on MPC5777C.
The errata e9570 of FCCU which mentions "FOSU may assert reset when a hardware recoverable fault of width less than one safe clock period occurs"
The workaround mentioned for this errata are
As a third workaround can the ALARAM interrupt be used with configurable time out in FCCU_NCF_TO.?
As the errata says “hardware recoverable fault of width less than one safe clock period”, this time can be programmed in FCCU_NCF_TO register to avoid the fault situation.
Is this approach can be used as workaround for this errata.?
Regards
Ravindra
Hi Ravindra,
The solution "workaround 3" is not a real workaround.
To achieve this you must program NCFS_CFGn registers and then you can use alarm.
Peter
Hi Peter,
Thank you for your reply.
I have enabled the fault sources for RCCU_0(10),RCCU_1(11), and Lockstep mode(42) in the registers FCCU_NCF_En.
For these sources NCFS_CFGn is configured as "No reset reaction" and NCFS_CFGn as "Hardware recoverable" fault.
Additional registers initialization to enable Alarm interrupt are as below:
FCCU_NCF_TOEn --> Timeout is enabled for fault sources 10,11, and 42
FCCU_IRQ_ALARM_ENn --> IRQ enabled for fault sources 10,11, and 42
FCCU_NCF_TO = 1 --> 1 RC clock
FCCU_EOUT_SIG_ENn --> Bistable Fault-Output enabled for 10,11, and 42
With these set of registers initialization,I am able to trigger interrupt for these sources by injecting fake fault in the register NCFF.
But the control is hitting the Fault interrupt again and again.
Is there i have to clear the alarm interrupt status register.?
Thanks,
Regards
Ravindra.
Hi,
This is quite simple and I have strongly recommend you to go trough my examples for FCCU published here:
MPC574xP - FCCU configuration guide
Check the MPC5744P_FCCU_alarm_state example to get a picture how to work with it.
Here are the steps:
1. Configure FCCU according my guide chapter 7. ALARM state
2. Inject fault
3. in ISR for FCCU alarm do:
a. read FCCU faults in NCFS_x
b. clear FCCU faults in NCFS_x -> this will automaticaly clear IRQ_STAT[ALARM_STAT] flag in FCCU.
Now no further interrupt are called from FCCU until next fault occur.
Peter
Hi Peter,
I will follow the steps mentioned in the FCC configuration guide and check the behavior.
Thank you,
Regards
Ravndra