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Old 04-25-2006, 01:28 PM
Jerome
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Default Virtex 2 Config Times

We are looking at using SRAM FPGA's for first time and trying to
get an approximate config time for say a XCV2P40 using the byte
wide bus vs serial bus to minimize time after reset. Assuming we
have to load 100% of the device can anyone provide an approximate
config time? Are we talking micro , milli or seconds ?

Also if the config time is too long are there any tricks that can be
played
to reduce it , short of removing functionality ?

Thanks!

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Old 04-25-2006, 04:28 PM
John_H
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Default Re: Virtex 2 Config Times

From the table in the Virtex-II Pro user guide, Configuration, Configuration
details, the approximate SelectMAP programming time for an XC2VP40 at 50 MHz
is 39.67 ms. This is an older data sheet version I'm looking at, so please
verify the numbers yourself.

"Jerome" <[email protected]> wrote in message
news:[email protected] oups.com...
> We are looking at using SRAM FPGA's for first time and trying to
> get an approximate config time for say a XCV2P40 using the byte
> wide bus vs serial bus to minimize time after reset. Assuming we
> have to load 100% of the device can anyone provide an approximate
> config time? Are we talking micro , milli or seconds ?
>
> Also if the config time is too long are there any tricks that can be
> played
> to reduce it , short of removing functionality ?
>
> Thanks!



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  #3 (permalink)  
Old 04-25-2006, 04:42 PM
Austin Lesea
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Default Re: Virtex 2 Config Times

Jerome,

http://direct.xilinx.com/bvdocs/userguides/ug012.pdf

See chapter 4.

There are 15,868,192 bits in the bitstream for a V2P40.

In the parallel modes of configuration, you can clock in 8 bits at a time.

http://direct.xilinx.com/bvdocs/publications/ds083.pdf

page 108 lists 66 MHz as the max CCLK.

So, with some math, gives 30 milliseconds to configure.

15,868,192/(8*66,000,000)=.0301 seconds

That is after the power on reset (part has reached all of its proper
operating voltages).

One trick is to use the compressed bit stream option which will copy
identical columns of memory (if there are any). Depends on your design.
If your design is very regular, you might gain significantly here.

Austin

Jerome wrote:

> We are looking at using SRAM FPGA's for first time and trying to
> get an approximate config time for say a XCV2P40 using the byte
> wide bus vs serial bus to minimize time after reset. Assuming we
> have to load 100% of the device can anyone provide an approximate
> config time? Are we talking micro , milli or seconds ?
>
> Also if the config time is too long are there any tricks that can be
> played
> to reduce it , short of removing functionality ?
>
> Thanks!
>

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