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RE: [microblaze-uclinux] Microblaze highest frequency.

Microblaze will only operate at 1:1 with the bus clock. i.e. if the bus
is at 100 MHz then BSB will setup Microblaze to run at 100 MHz as well.
The "Reference Clock Frequency" is the clock that is brought into the
system and stepped up or down as needed to create the bus clock.

Bruce Karsten

Xilinx, Inc.

Processor Specialist - North Central US

Hoffman Estates, IL

 

-----Original Message-----
From: owner-microblaze-uclinux@xxxxxxxxxxxxxxxxxxxx
[mailto:owner-microblaze-uclinux@xxxxxxxxxxxxxxxxxxxx] On Behalf Of
Nicolas Herve
Sent: Wednesday, May 27, 2009 1:53 PM
To: microblaze-uclinux@xxxxxxxxxxxxxx
Subject: Re: [microblaze-uclinux] Microblaze highest frequency.

2009/5/27 Andreas Hofmann <ahofmann@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>:
> [...]
> What maximum delay does your synthesis run report?


I mean the system clock (indeed the "Processor-Bus clock frequency")
still is at 100MHz, and have selected the 400 MHz for the CPU only in
the bsbwizard (at least, I though it wat, indeed it is named
"Reference Clock Frequency"). Compilation success with the Xplorer
Scripts option [1] without any complaint.
Then I presume that the CPU is configured for 400 MHz clock frequency.

After have a look in the synthesis/microblaze_0_wrapper_xst.srp
generated file I found the following :

> Timing Summary:
> ---------------
> Speed Grade: -10
>
>   Minimum period: 8.832ns (Maximum Frequency: 113.225MHz)
>   Minimum input arrival time before clock: 5.536ns
>   Maximum output required time after clock: 5.922ns
>   Maximum combinational path delay: 3.994ns

Is it just for the wrapper ?
and in synthesis/system_xst.srp I have:

> Timing Summary:
> ---------------
> Speed Grade: -10
>
>   Minimum period: 3.274ns (Maximum Frequency: 305.446MHz)
>   Minimum input arrival time before clock: 2.583ns
>   Maximum output required time after clock: 6.921ns
>   Maximum combinational path delay: No path found


I am a bit confused ...


[1] - in Menu:Project -> Project Option, "Hierarchy and Flow" tab,
"Effort Level to Run Implementation Tools" list. And I let the "Treat
timing closure as an error" to be sure.
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