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Re: Unneeded SH4 boards


Are there any chance to use some NAS devices as cheap development board?

I have some of pretty old NAS devices running on SH4, which I used to run
debian (etch?) to try building its packages.
# Tough I've given up blindly dealing with bootloaders and kernel updates...
# because of playing it without any consoles. switch on, and pray to boot up.

On Wed, Oct 28, 2015 at 8:08 PM, Oleg Endo <oleg.endo@t-online.de> wrote:
> On Wed, 2015-10-28 at 11:05 +0100, John Paul Adrian Glaubitz wrote:
>> On 10/28/2015 02:23 AM, Vladimir Zapolskiy wrote:
>> > please correct me, if I'm wrong, but I believe Debian SH4 port is
>> > practicably unusable for years.
>> It's not, what makes you think so? I have invested lots of efforts
>> recently to get the port back into shape and together with the
>> help of upstream developers for the toolchain (gcc, binutils etc)
>> and the kernel we managed to fix many bugs and got the boards
>> running with recent kernel versions and gcc-5. I still continue
>> working on the port.
> The problem with the current SH4 debian, or actually with SH4*-linux
> -anything is the model selection of atomic operations.  As far as I
> know debian uses the default which is gUSA.  This is not so good for
> SH4A systems... maybe we should fix this somehow in the near future.
> Also, just out of curiosity ... which boards are supported by SH4
> debian?  I'm not sure if a generic SH4 / SH4A Linux kernel is possible
> at all..
>> > The SH4 core architecture is pretty old,
> "Old is gold" :)
>> > but I have some interest in its
>> > support related to Open Hardware initiatives, but my problem is
>> > that I
>> > can not find any SH4 reference boards for sale (digikey has only
>> > one
>> > from Renesas, but its price is too high for me, about $800 for a
>> > board
>> > and LCD).
>> Yeah, those boards are pretty hard to come by outside Japan. I visit
>> Japan regularly but I always keep on forgetting looking for
>> additional
>> boards in Akihabara or other places.
> A while ago I bought this
> http://www.apnet.co.jp/product/superh/ap-sh4ad-0a.html
> But I haven't had any time to make Linux work on it.  The images they
> provided on Sourceforge use Linux Kernel 2.4 or 2.6 (don't remember)
> and are probably not so useful anymore.  The vanilla Linux Kernel has
> support for this board, but it enables only one core (out of 2 cores)
> and L2 cache is also not enabled.  I don't know the reason, maybe some
> of the SH4A multi-core stuff is not working properly.  As for the L2
> cache, some other SH4A boards had problems and then people "fixed it"
> by turning it off ...
> Alpha Project has many other SH boards:
> http://www.apnet.co.jp/product/superh/index.html
> They also ship to outside of Japan.
> Another interesting SH4A board is this:
> http://www.luna-nexus.com/jp/pdf/SH7753_board.pdf
> The biggest drawback of those boards for running Linux is the
> relatively small amount of RAM.  The prices are also not very hobbyist
> friendly.  It's a very niche market (small demand = high price).
>  Probably you will not find anything for less than 500 USD.
> I have a bunch of Dreamcast boxes and probably they are still easy to
> get on eBay or other market places.  But with 16 MByte RAM it's
> probably really difficult to get a usable Linux system running on it.
>  A PATA harddisk can be connected relatively easily, but transfer speed
> is limited to something around 25 MByte/sec.  Ethernet is even more
> difficult ...
> Cheers,
> Oleg


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