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NMI and the SSL:adi_int_CECHook, where's the RTN?

Question asked by Colin on May 21, 2010
Latest reply on Jun 1, 2010 by SteveM


  I'm using the SSL (but not VDK) and successfully so far.  I've reached the point where I'd like to implement the Power-Failure handling and so I'm trying to hook the NMI.


1)  I can't find any description of the NMI pin's behaviour (is it level or edge sensitive?)  Does the handler have to take any action to clear the interrupt and prime it ready for the next NMI?  If the NMI signal is, say 10ms long, can the handler complete and return, before the NMI returns to it's inactive level, without another NMI occuring immediately?


2) Is  adi_int_CECHook() the way to get access to the NMI events?   It certainly works to hook the interrupt and my supplied handler routine (ending with an RTS as descibed) returns to the SSL.  However tracing through the SSL, after an NMI event with the debugger, does not show any RTN instruction and the code never returns to the address it was interrupted out of.   I can see where it came from using the Trace feature and I can see the correct return address in RETN.


3) Should the NestingFlag parameter of adi_int_CECHook be TRUE of FALSE?  What effect will it have on NMI?


FYI: I'm using VDSP 5.0 Update 7. on a BF534, debugging with a HP_USB ICE.




Colin Moloney.