AnsweredAssumed Answered

MPC5777C reset escalation: any unpublished errata?

Question asked by Andrew Dennison on Apr 30, 2017
Latest reply on May 16, 2017 by Peter Vlna

"5.7.7 UTEST Reset Escalation Configuration DCF client" states that the default value for bit 31, REE, is 0 indicating reset escalation is disabled. Reading SIU_RCR in code I also see that this register is all 0, so the 4 RET bits appear to be loaded with 0 to disable reset escalation. However, if I reset the CPU 5 times with SIU_SRCR[SSR] or the external RESET pin the RSTOUT remains low until a POR is generated by removing and reapplying CPU power.

 

Reading SIU_RCR[RET] I have never seen a value other than 0, however despite this if I then write 0 to SIU_RCR prior to the next software or external reset I can continuously reset the CPU without RSTOUT remaining low.

 

As such it appears to me that reset escalation is always active in some form with the 2N45H mask.

 

Naturally I can work around this in a controlled environment, however I discovered the above when trying to understand why our hardware sometimes fails to start and I found RSTOUT was remaining low in these cases.

 

Currently we are not writing a DCF record for reset escalation client - would it be appropriate to write two records: one with REE = 1 then another with REE = 0, much like the workaround documented in e9784 for the REE TMPSNS DCF client?

 

Does the 3N45H mask exhibit this same behaviour?

Outcomes