Internal flash programming of MPC555

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Internal flash programming of MPC555

by Sushmitha :: Rate this Message:

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Hi,

When I program MPC555 board individually , It is booting and working
properly. But when MPC555 board is integrated with other boards in the
application, programming of internal flash is not happening.

Can PORESET may create any issue regarding this? As the same signal is
used in other boards. The total trace length of PORESET signal
navigating is 10 inches when other boards are integrated. Can this
show an effect in time delay(fall time) of the poreset signal?

Or any other options may cause this issue?

Thanks & Regards
Sushmitha



Re: Internal flash programming of MPC555

by Mark Allison :: Rate this Message:

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You don't say if your 555 is actually doing anything at all or just
not reprogramming.

Track length can potentially cause issues with high speed signals
especially.
Too many devices placing too much load on a single line will screw up
signals so maybe you need some buffering.
A poorly terminated line could cause reflections.
Presumably if you have many devices sharing a single PORESET they are
also sharing the same power supply so maybe that's overloaded?
Shorts, Open circuits etc etc
There are many things that could be causing your problem but it would
be very difficult for anyone to diagnose a problem in a multi-
processor system without seeing it.

I'd go back to the hardware engineers that designed your system and
ask them if they've considered all these things and get them to stick
a scope on it :)

--- In MPC500@..., "Sushmitha" <sushmi_reddy2003@...>
wrote:
>
> Hi,
>
> When I program MPC555 board individually , It is booting and
working
> properly. But when MPC555 board is integrated with other boards in
the
> application, programming of internal flash is not happening.
>
> Can PORESET may create any issue regarding this? As the same signal
is
> used in other boards. The total trace length of PORESET signal
> navigating is 10 inches when other boards are integrated. Can this
> show an effect in time delay(fall time) of the poreset signal?
>
> Or any other options may cause this issue?
>
> Thanks & Regards
> Sushmitha
>