[Oberon] Oberon board availability (was Moving oberon to RISCV?)

Chris Burrows chris at cfbsoftware.com
Sat Jul 28 08:24:41 CEST 2018

That is an excellent summary. I have a few additional comments based on my
experience of the Pepino:

1. Although Pepino was specifically designed to run Project Oberon it does
has other uses. My retrocomputing interests include Modula-2 compilers and
68000-based systems (Sage, Mac, Atari, Amiga and Palm). One of Pepino's
alter-egos is the MacPlus. Using it somehow feels more like the real thing
than using a Mac emulator on a PC. I have a few other long-term projects in
mind to make use of its 68000 personality. 

2. I have the LX25 version of the Pepino as well as the LX9. It has an
additional 1 MB of SRAM making a total of 2 MB. Unfortunately the Pepino
LX25 is listed as discontinued. However, I'd be surprised if Magnus didn't
resurrect it if there was sufficient demand. 

@Magnus: What would a minimum order be to make this happen?

3. The Pepino can run Project Oberon RISC5 Workstation at 37.5 MHz using the
alternative Verilog code on Saanlima's site.

... and just to show I'm not biased ;-)

4. Pepino uses the Xilinx Spartan-6 which is not supported by the latest
Xilinx HDL software (Vivado). If you want to modify the Verilog code for the
Pepino the older ISE 14.7 software is still available but it requires a
Linux VM to run it on Windows 10. I prefer using the Vivado software with
the Artix-7 (as used by RiskFive).

Chris Burrows
CFB Software

> -----Original Message-----
> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
> Skulski, Wojciech
> Sent: Saturday, 28 July 2018 12:07 PM
> To: ETH Oberon and related systems
> Subject: Re: [Oberon] Oberon board availability (was Moving oberon to
> Magnus wrote:
> >Or you could buy a new Pepino Oberon Kit from Saanlima Electronics
> with
> >an Oberon system ready to go, just add monitor, keyboard, mouse and
> >cable.  The kit is normally $104.95 but is currently on sale for 20%
> >off (use coupon OberonGo at checkout).
> Excellent. I am glad you are pointing it out. We have one such Pepino
> board. It is working very well. I will add the pointer to the
> RiskFive website.
> So I should explain the difference between Pepino and RiskFive.
> 1. RiskFive kit is 10x more costly than Pepino. (OK, at this point we
> have lost all the customers ;-)
> 2. Pepino aims at running the original 2013 Oberon System. RiskFive
> was designed to advance the Oberon System beyond the current status.
> 3. Pepino + Oberon just works and it is ready to go. RiskFive lacks
> any working FW at this point, because it intentionally provides new,
> high performance hardware. The FW and the corresponding SW drivers
> need to be developed.
> 4. FW/SW developments are of course possible with Pepino, but there
> is no nagging reason to pursue such modifications because Pepino just
> works. It is also not clear, what these modifications should be,
> because "don't fix it if it ain't broken". In case of RiskFive, its
> FW/SW *must* be fixed because it does not even exist yet.
> 5. RiskFive is a development platform for non-Oberon applications as
> well. It can accommodate FPGAs up to Artix 100T, which is sufficient
> for RISC-V. (Any takers?) Soldering Artix 100T will boost the kit to
> some $1,200. But hey, if you want to betray Professor N.Wirth and go
> to the Berkeley bunch instead, then you deserve the punishment.
> 6. Pepino has a rather limited set of GPIO pinned out to 0.1"
> headers. These are good for the low and mid-performance apps like
> pushbuttons, PWM, and so on. In case of RiskFive, all the pins that
> are not occupied for ZBT, were pinned out to high performance Hirose
> connectors with integral ground. (Most were routed differentially.)
> These can be driven at the full speed that Artix can deliver, which
> is over 1 gigabit per second per pair.
> 7. Pepino is a closed ended design. RiskFive is open ended in the
> sense that the end-user functions are on the motherboard which is
> relatively easy to modify. (I will post the design files.) The
> division between the high-performance core module and the user-mode
> motherboard is intentional. The core module is "just the FPGA",
> memory, boot flash, and power. All the application stuff is on the
> motherboard which is meant to get modified.
> 8. Pepino cannot provide a rich multicolor display due to limited
> RAM. Four colors are the limit. (Magnus has implemented the four
> color display. Many thanks!) RiskFive has enough RAM to support
> 1k*768 (or even slightly larger) of 8-bit pixels, mapped to 24 bit
> color via a lookup table. (A palette.) It was one of the main goals
> driving this design. Note that the video is on the motherboard, what
> hints that some planned applications will be deeply embedded w/o the
> display. Ditto with the mouse and keyboard.
> 9. Another hint at such deeply embedded application is the presence
> of GbE PHY on the core RiskFive module. This PHY is not planned to be
> used with Oberon, unless we can find some really brave soul to
> implement the Ethernet MAC in the fabric and the Internet stack in
> Oberon. I am not counting on this. The PHY is meant for software-less
> apps outside the Oberon realm.
> 10. Pepino can run RISC5 at 25 MHz. The clock speed is limited by the
> ASRAM chip. It is the same performance as the original 2013 Oberon,
> and for he same reason. This limitation is lifted in RiskFive, whose
> synchronous RAM can be clocked up to 250 MHz. I will push my interns
> to achieve 100 MHz RISC5 operation. Faster operation is allowed by
> the ZBT memory and we can try pushing even beyond 100 MHz.
> 11. In summary, RiskFive is definitely not "ready to go". It is an
> adventure which is just beginning. I hope that the journey will
> continue.
> Thank you,
> Wojtek
> --
> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related
> systems https://lists.inf.ethz.ch/mailman/listinfo/oberon

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