Re: [oc] Modular FPGA board

[John Dalton <johnd@southern-poro.com>]

> Very good idea, but is there some open core with PCI master/target
> interface? I don't think so. Are you planning to use comercial chips for
> PCI interface?

I'm planning to do PCI in an FPGA.  For this entire project, I would like
to reuse any relevant work which has been done on the OCRP-2.  The
free PCI core is not yet finished, but the availability of a board might
provide the impetus for this work to progress.

On the subject of reusability, it shouldn't be too hard for someone to
build each of the OCRP-2 peripherals onto a SIMM, allowing an
OCRP-2 clone to be built. The main reasons for not just using an OCRP-2 are:
1) improved expandability (adding new things)
2) improved upgradability (replacing old things with new things)
3) improved customization (not having to pay for unused peripherals)

The current dilemma I am dealing with is that putting 2 FPGAs (1 PCI, 1 main)
on the motherboard means two expensive chips, which are hard to remove, cannot

be upgraded independently.  I'm currently figuring out how to make PCI a
module,
(along with ISA, EISA, etc.) while still satisfying mechanical (and
electrical)
constraints, and not spending a fortune on connectors.  FPGAs, with enough
pins
to do PCI, don't seem to fit in cheap sockets.

Another argument for modular PCI is that a double sided edge connector is hard

to do at home.

> 1.6mm PCB doesn't fit into a 72 pin SIMM slot. And here in Brazil, 1.27mm
> is much easier to build (BTW, I have never seen a 1.6mm thickness PCB).

A pity.  Here in Australia, 99% of PCBs are 1.6mm (1/16") thick.  (Including
most imports.)  1.27mm (0.05") is used for special applications, such as
SIMMs.
As a result, the electronic chain stores stock only 1.6mm. 1.27mm can be
bought,
but it is harder to get.

> Again, here in Brazil it's becoming difficult do find SIMMs, and when
> someone is able to sell or trade SIMMs, it costs more than the double
> price of the DIMMs of the same memory capacity.

Opps.  Incorrect use of terminology by me.  I meant to inquire about
the global availability of 72 pin SIMM *sockets*.  They seem to be
available in AU, though not from the major chain stores.