[Oberon] New FPGA Oberon board

[skulski at pas.rochester.edu]

Hello:

 trying to define our own specs is the biggest mistake we can possibly
make. We are a small community. Too small to take advantage of the economy
of scale. Anything of our own will cost a lot to make in small numbers.
Seemingly trivial items like enclosures will be either very costly or
impossible to manufacture. I have been there. I made this mistake. I
learned the lesson.

There is one possible way to beat the economy of scale while being small.
Join someone else's standard and design in a form factor that is exactly
compatible. Electrically, pin to pin exactly the same.  Then you can use
their expansion boards. Mechanically, the same dimensions and the same
mountig holes. The same external connectors in the same exact places. Then
you can use their enclosures. You do not have to think where to get those
little trivial pieces, which in practice make a huge difference.

If you agree on that, then the next question is which bandwagon to jump
on. I vote for BeagleBone Black (BBB). It defines the set of interfaces,
such as the mouse, keyboard, SD card, HDMI, and pin connectors. The boxes
(very nice ones!) cost five dollars a piece. There is a growing number of
expansion boards, which you can adopt without designing your own. The
expansion card specs are rigidly defined. These are called "capes". The
design files for most capes are available in either Eagle or OrCAD. I am
now finishing the design of a very advanced "cape". It took me about three
weeks (maybe four) from scratch. If this community moves forward with the
BBB path then I can contribute the template schematics and the preplaced
layouts of the connectors, holes, power, and several others. This I can
discuss offline with the actual designer.

Why BBB rather than Arduino, RPi, or whatever other great board?

1. The BBB is truly open source. All the design files are available. RPi
is closed source. Others I do not know.

2. BBB has a lot of expansion pins. Others do not. You will be surprised
how many pins you will need in future. Do not cripple yourself at the
start. BBB standard will not cripple us.

3. Lots of BBB capes are available, from simple to complex. There will be
many more available because BBB is gaining momentum. All of these will
become immediately available to the Oberon community, if we design to this
standard.

4. I designed a few pieces in this standard and I will design more. I can
share the building blocks such as connectors, power, etc.

5. I can advise the actual designer behind the scenes, or maybe even share
some of the design burden (within reason).

Closing remarks:

I am ready to advise which FPGA, Spartan-6 or Artix. I vote for Artix and
I can share the schematics of Artix-FG484. All Artix chips fit into this
footprint, so it is a very future-oriented design path.

Concerning the memory, I vote for ZBT RAM such as IDT71T75602/IDT71T75802
(2 MBytes in a single chip). It is faster than asynch (166 MHz) and it is
truly clocked. Hence, no pesky timing because the RAM will be synchronous.
At the same time, it avoids the complexities of DRAM.

I hope you will find this discussion of some help in reaching the decision.

Thank you,
Wojtek




> New FPGA Oberon board (greim)
> Date: Sat, 16 May 2015 14:51:55 +0200
> From: greim <greim at schleibinger.com>
> Subject: [Oberon] New FPGA Oberon board
> To: oberon at lists.inf.ethz.ch
> Message-ID: <55573D6B.2070401 at schleibinger.com>
> Content-Type: text/plain; charset=windows-1252; format=flowed
> Hello Magnus,
> Hello Chris,
> An FPGAOberon board would be great!
> My suggestions:
> - Baseboard incl. FPGA, SRAM (incl. Goldcap or battery buffer), SD-Card
>    (usable as standalone embedded system).
> - All interfaces (PS/2, Keyboard, VGA or HDMI..on a extra shield or
breakboard. Maybe following the mechanical and electrical specs of the
Arduinio (DUO, Mega?) shields. This standard is not only used by
hobbyists also TI, Intel etc. are now offering evaluation boards with
this interface.
> - More I/O space for external individual hardware. I know we are running
out of the I/O lines. Maybe using one or two SERDES chip.
> - More SRAM to bring color in the  future of Oberon!
> Should we start a Kickstarter Project?
> Maybe some support from Xilinx? I can imagine, after the paper presented
in their journal, there maybe some feedback from Universities etc.
Regards
> Markus Greim
> I will cross-post this message in the Oberon list and in the Saanlima Forum