Re: sreset and hreset in mpc565.

> Hi!
> Im haveing some problem on one of 4 in-development-mpc565-using-cards.
>
> The problem is that they should be all identical, but on one card
> sreset and hreset are 0v. On all others sreset and hreset are 5v,
> since of the pullup resistor.
>
> Now i just wonder if that indicates that the processor is broke, or if
> there are other pins that could cause this error? For example the
> POWER ON RESET pin is correct, same as on fully working cards.
>
> Since there has been certain modifications done, it is possible that
> they are not fully identical, though they should.
> If someone could give me a clue about it, i woud really appreciate
> that.
>
> //Daniel
>
>

The mpc565 can drive the HReset and SReset signals itself.  When it sees a
(low) POReset signal, it will drive HReset and SReset low for a while.  It
first releases HReset, after certain basic functions are in order (I can't
remember exactly, but at least the clock should be up and running, and the
databus sample for reset configuration if you are using that).  After a
brief delay, SReset will then be released.

If your POReset signal is high, then it seems your processor is keeping the
HReset (and therefore SReset) low for some reason.  The most likely guess is
that it has not managed to get the clock running properly.




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