Re: Unneeded SH4 boards
On Mon, 2015-11-09 at 22:09 +0200, Vladimir Zapolskiy wrote:
> Hi Oleg,
>
> On 09.11.2015 16:07, Oleg Endo wrote:
> > On Mon, 2015-11-09 at 15:41 +0200, Vladimir Zapolskiy wrote:
> >
> > > Oleg, thank you for the links, but all the boards are too
> > > expensive for me, unfortunately...
> >
> > Yeah, I know the prices are crazy...
>
> ... and I completely don't understand why :(
It's the effect of the simplest rule of economics:
low demand - high prices
The cheapest SH4 SH775x chip on digikey is 40 USD. A more recent SH4A
(SH7724) chip is listed at 46 USD. And you can even still buy SH1
(SH7034 etc) chips at 20 USD. As you might see, there is no
relationship of price and performance/features. This is simply because
of the above rule. Renesas (and other companies at its size) has very
long availability times. But something has to keep the ship afloat,
pay salaries, rent, maintain parts stocks etc etc.
You can also check the prices of some of the PCB shops out there. For
example, a 15 x 15 cm 6 layer PCB is about 130 EUR at a quantity of 4
boards.
Stuff gets a lot cheaper as volume increases. But then somebody has to
take the risk of making an upfront investment.
> > On top of that, you'd also need some flash programmer or something
> > to get a bootloader/kernel image into the NOR flash. So it's
> > actually even more expensive.
>
> if a board has JTAG interface, I believe it should be doable for me
> to
> add SH4 support to OpenOCD and then flash images with any cheap JTAG
> -USB
> dongle.
Yeah, usually there's a JTAG port. But documentation of the JTAG stuff
is really poor and so far I have only seen commercial software support
for it. So it might be a bit of work to get the stuff up and running
with OpenOCD.
Cheers,
Oleg
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