On Tue, 12 May 2009 08:13:37 -0700 (PDT), lolita.tangier@gmail.com
wrote:

|i tried a description of RAM but i can't syntesize it and i have
|the following error:
|
|ERROR:Pack:18 - The design is too large for the given device and
|package.
|
|i think i will be to use the external SRAM FPGA's board, but i don't
|know if i can use it without EDK and how i can read and write in this
|SRAM.
|===========


You do not need EDK to access the onboard SRAM. Webpack is sufficient.

You just need a simple SRAM interface with enough address, data and
control lines to store and read data from it.

james

lolita.tangier@gmail.com writes:

> i tried a description of RAM but i can't syntesize it and i have
> the following error:
>
> ERROR:Pack:18 - The design is too large for the given device and
> package.
>
> i think i will be to use the external SRAM FPGA's board, but i don't
> know if i can use it without EDK and how i can read and write in this
> SRAM.

You'll have to put an external memory interface into your design.

You may or may not realise, so I'll point it out - XPS won't magically
take your large RAM and put some of it into external memory, you'll
have two RAM elements (assuming you keep a smaller version of your
current memory) and you'll have to use the software linker file to
allocate different parts of your data to those blocks.  

And if you want to put code or initialised data in the external SRAM
you'll need a bootloader system to pull the initialisation data out of
your configuration device (or somewhere else non-volatile).

Cheers,
Martin

-- 
martin.j.thompson@trw.com 
TRW Conekt - Consultancy in Engineering, Knowledge and Technology
http://www.conekt.net/electronics.html

On 12 Mai, 17:13, lolita.tang...@gmail.com wrote:
> i tried a description of RAM but i can't syntesize it and i have
> the following error:
>
> ERROR:Pack:18 - The design is too large for the given device and
> package.
>
> i think i will be to use the external SRAM FPGA's board, but i don't
> know if i can use it without EDK and how i can read and write in this
> SRAM.

Hi lolita,
You didn't tell us how much RAM you need and which FPGA you are about
to use.
Generally, RAM inside an FPGA is quite limited. Take a look at the
datasheet how much BlockRAM and distributed RAM are available in your
chosen device
and keep in mind, that distributed RAM consumes LUTs so minimizes the
ressources for the rest of your design.
Do these calculations before you implement anything.

On using external SRAM:
If you have an ordinary design, you don't need EDK to use SRAM.
Simply connect your address lines of your design to the FPGA pins
where the SRAM adresses are, and do the same for data and control
lines. that's it
You will find that information in the board documentation if you buy
some board "of the shelf".

If you are doing some MicroBlaze design, you are using EDK anyway and
for the microblaze EDK comes with an IP-Core to connect MB and SRAM.
Still you need to update your UCF file to connect to the right pins.

Have a nice synthesis
   Eilert

On May 12, 11:13=A0pm, lolita.tang...@gmail.com wrote:
> i tried a description of RAM but i can't syntesize it and i have
> the following error:
>
> ERROR:Pack:18 - The design is too large for the given device and
> package.
>
> i think i will be to use the external SRAM FPGA's board, but i don't
> know if i can use it without EDK and how i can read and write in this
> SRAM.

it's easy to read or write sram using fpga

Try decreasing the size of leds/push/dip (if applicable) on the
address tab of system assembly view.



On May 12, 4:13=A0pm, lolita.tang...@gmail.com wrote:
> i tried a description of RAM but i can't syntesize it and i have
> the following error:
>
> ERROR:Pack:18 - The design is too large for the given device and
> package.
>
> i think i will be to use the external SRAM FPGA's board, but i don't
> know if i can use it without EDK and how i can read and write in this
> SRAM.

<lolita.tangier@gmail.com> wrote in message 
news:8c3adb4f-d8b7-4b74-aae5-199208feefc9@r36g2000vbr.googlegroups.com...
>i tried a description of RAM but i can't syntesize it and i have
> the following error:
>
> ERROR:Pack:18 - The design is too large for the given device and
> package.
>
> i think i will be to use the external SRAM FPGA's board, but i don't
> know if i can use it without EDK and how i can read and write in this
> SRAM.

Search the docs for examples on loading the configuration from serial flash. 
Avnet has a few good tutorials on how to do this on their boards in 
particular. The concepts apply to others boards in general.

i tried a description of RAM but i can't syntesize it and i have
the following error:

ERROR:Pack:18 - The design is too large for the given device and
package.

i think i will be to use the external SRAM FPGA's board, but i don't
know if i can use it without EDK and how i can read and write in this
SRAM.