Date   : Mon, 19 Jan 2004 18:30:50 GMT
From   : Chris Johns <chris.johns@...>
Subject: Re: NMI Handlong on the Electron

> > When you've finished handling the NMI, you're meant to set the NMI clear
> > bit (bit 7 of &FE05) which tells the ULA it can have the RAM back.
> >
> > Anyone any ideas?
> 
> Try JMP &FFAC instead, this is special Electron NMI exit code,
> Sprow.

Tried that (instead of the RTI) but it does the same. I'm wondering if
there is some hardware timing issue thats causing it to have problems,
although it all seems to work fine, except for the screen corruption.

I seem to recall something about the NMIs needing to be on the edge of
something else, I think PHI OUT.

I might start with looking at a simpler example, in the form of NetMon -
which does all its NMI handling, if I can get that to work then I can
attack the NFS ROM again.

-- 
 <chris.johns@...             >