Re: omission of CFG REG in FPGA for embeded system

["Hiroaki Okumiya" <OKUMIYA@jp.ibm.com>]

Mano-san, Monish-san, Thank you for quick advice.
Now It become clear. I can omit configuration registers with confidence.

>May I ask which vendor's FPGA you are planning to use?  Also, are you
>designing your own PCI interface?

Of course. I use Altera Flex10KE and PCI I/F is our original design.
And it has  already become to work on prototype card.

 Okumiya Hiroaki  ADTX Co.,Ltd.

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>I am developing  the embeded card with PCI BUS.
>There are Three PCI devices "HOST-PCI bridge","FPGA designed by me",
>and "PCI SCSI CARD (any card can be attached)" .
>My question is :
>Is there any possibility that 3rd vendors SCSI card will access to
>configuration registers in FPGA ?
>If the answer is No, I want to hard wire all configuration value
>(Base Address,etc), and ignore all configuration access.
>Because this product is closed embeded card and we are prgraming
>MPU code and we need not change configuration registers.
>Is there some problem to omit configuration registers ?

This should be fine.  I'm sure the SCSI device would not access anyone's
configuration registers.

Incidentally, I'm also working on an FPGA that connects to PCI within an
embedded system.  I'm planning to omit the configuration space entirely.
The software for this system will know that my chip is there - it doesn't
need to find it by scanning configuration space.

May I ask which vendor's FPGA you are planning to use?  Also, are you
designing your own PCI interface?

> Okumiya Hiroaki  ADTX Co.,Ltd.
>http://www.adtx.co.jp/english/

Monish

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The answer is No. The SCSI card does not have access to the FPGA IDSEL (a
point to point signal) and therefor can not generate CFG cycles at all.
In a close embedded system you can ignore the configuration cycles if you
wish.

Oren Mano
EMC Corporation