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Altera_Forum's avatar
Altera_Forum
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15 years ago

Using EPCS128 memory with StratixII GX?

Hi,

I have run into a problem. My board has an EPCS128 and a stratixII GX (EP2SGX60DF780C4) device. I am using the remote update megawizard function to choose different FPGA images inside the flash memory.

It seems that there is no way for the remote update module to address the entire EPCS128 memory space since the remote update module only addresses bits 22..16 of the 24-bit address space. This would render the EPCS128 crippled for designs using stratixII devices. Is there a way around his or am I missing something?

Regards

Jens

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    What it basically means is that you can only use the first 32 sectors of the EPCS128 device as configuration addresses. You are correct that the remote update core does not have access to the upper half of the EPCS device.

    However, how many FPGA configuration images do you need to store. I would estimate you could probably fit 8 compressed images of the EP2SGX60 in the first 64Mbit of the flash.

    Jake
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    This means the EPCS128 memory is not for stratixII. I can acheive the same functionality using the EPCS64?

    The FPGA image is about 975kbyte compressed and the FPGA is fit to 45% by Quartus. My guess is that the image could worst case be about 15-1600kbyte if the FPGA is fit to say 90% and compression is used. Am I wrong?

    Jens
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Some people use the EPCS flash for non-volatile storage other than storing FPGA images. For example, you can still access the upper half of the device to store configuration data and such. You just can't boot from those locations.

    The size of the file does not really scale linearly with the fit percentage. I would count on a minimum compression of 35% of the uncompressed files size (2.119 MB for EP2SGX60). Most likely you'll get better than that. So you could say 1.5MB as an upper limit but It may be that you remain under the 1MB mark.

    Jake
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Ok, thankyou for your replies. I was a bit disappointed at this limitation. I created an image with a 95% fit and it is about 1.2Mbytes compressed.

    Is the address space limitation hard-wired in the silicon or can I write my own remote update module?

    Jens