[Oberon] Spartan 6 Kickstarter project

[Jörg Straube]

Yeah, the wrong package :-(
Br, Jörg

> Am 23.06.2014 um 18:45 schrieb Ulrich Hoffmann <uho at xlerb.de>:
> 
> Hello Jörg, Paul,
> 
> according to Jack Gasset, developer of the Papilio DUO, the 2MB RAM on the Deluxe board
> is organized by 8 :-(
> 
> He wrote:
>> Unfortunately there are not enough free pins with the Spartan6 tqfp package used on the Papilio DUO to pull that off. The 2MB SRAM is an 8 bit part.
> 
> Thanks Paul for pointing this out and explaining the simplicity philosophy.
> 
> Regards,
>        Ulrich
> 
>> Am 23.06.2014 um 15:43 schrieb Jörg:
>> 
>> Hi Paul
>> 
>> Today's RISC5Top Verilog source splits the 20 bits address bus to
>> two SRAM chips with 18 bits address and 16 bit output.
>>                                 +------+
>>                               +-! 256K !-- 16 bit
>>                               ! +------+
>> adr (20bit) --- SRadr (18bit) --+ 
>>                               ! +------+
>>                               +-! 256K !-- 16 bit
>>                                 +------+
>> 
>> As the Papilio DUO page only points to ONE SRAM datasheet (IS61WV5128)
>> but offers TWO versions of the board (512K and 2M) I could imagine that
>> the 2M version has 4 of those chips in parallel.
>> 
>> If this is the case, today's "RISC5Top" Verilog could be re-written to
>>                                 +------+
>>                               +-! 512K !-- 8 bit
>>                               ! +------+
>>                               ! +------+
>>                               +-! 512K !-- 8 bit
>> adr (20 bit) --- SRadr (18bit) -! +------+
>>                               ! +------+
>>                               +-! 512K !-- 8 bit
>>                               ! +------+
>>                               ! +------+
>>                               +-! 512K !-- 8 bit
>>                                 +------+
>> 
>> The upper half of those SRAM chips would not be used...
>> 
>> br
>> Jörg
>> 
>> 
>> -----Original Message-----
>> From: Paul Reed [mailto:paulreed at paddedcell.com] 
>> Sent: Montag, 23. Juni 2014 13:45
>> To: ETH Oberon and related systems
>> Subject: Re: [Oberon] Spartan 6 Kickstarter project
>> 
>> Hi Ulrich, (bcc others)
>> 
>>> the Papilo DUO kickstarter project [1] (4 days to go) has 2MB SRAM (not
>>> SDRAM) on board of its PAPILIO DUO DELUXE.
>>> 
>>> With the Classic Computing Shield you also get VGA output, 2 x PS/2 and
>> a micro SD socket.
>>> 
>>> Looks to me, that's what you need for RISC-Project-Oberon, right?
>> 
>> https://www.kickstarter.com/projects/13588168/papilio-duo-drag-and-drop-fpga
>> -circuit-lab-for-mak
>> 
>> Looks perfect, but the devil is in the detail, as always.  I think their
>> SRAM is x8, so even though it's a good speed (10nS), the board seems to be
>> designed for retro 8-bit processors not 32-bit RISC.  The Digilent
>> Spartan-3 board has two x16 10nS SRAMs set up in parallel, which is why
>> it's so neat.
>> 
>> However, maybe things are changing - it's refreshing that the Papilio
>> project description says: "SRAM - Easy to use SRAM is a must. We've used
>> SDRAM in the past and it was a big mistake! The strict timing requirements
>> and interfacing caused fits for everyone. SRAM is asynchronous and dead
>> easy to use, you will greatly appreciate the simplicity of SRAM in your
>> projects."
>> 
>> People privately email me questions along the lines of: "would it be
>> possible to port the RISC Oberon system to FPGA board X".  I'm BCC'ing
>> some in, and suggest they perhaps follow the Oberon mailing list instead
>> to understand why it's currently a very difficult question to answer. 
>> Whilst I would be absolutely delighted to see something viable, "possible"
>> is not the same as "easy" or even "sensible".
>> 
>> The point of Project Oberon is not just to make something work, starting
>> from scratch, but to make it completely clear and understandable (and
>> convincing).  The entire book is just that, and amply rewards a careful
>> read.  I think it's only after you read the whole book through that you
>> can really start claiming to understand the philosophy.
>> 
>> F V Tkachov (2014 J. Phys.: Conf. Ser. 523 012011) recently perhaps put it
>> even more starkly than Prof. Wirth: the natural tendency towards
>> unnecessary complexity creates vulnerability (The Kalashnikov Principle),
>> and should be avoided.
>> 
>> Cheers,
>> Paul Reed
>> http://projectoberon.com
>> 
>> 
>> 
>> --
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
>> https://lists.inf.ethz.ch/mailman/listinfo/oberon
>> --
>> Oberon at lists.inf.ethz.ch mailing list for ETH Oberon and related systems
>> https://lists.inf.ethz.ch/mailman/listinfo/oberon
> 
> 
> --
> 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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