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Subject: Re: SD Card BUS royalties on a new hardware

Re: SD Card BUS royalties on a new hardware

From: Jorge Pinto aka Casainho <>
Date: Fri, 10 Apr 2009 08:28:41 +0100

Thanks everyone who did answer :-)

Probably we will end using the SPI bus to avoid the royalties and is
nice to know that at 25% less speed (25MHz bit speed) it should be ok
for listen the audio from the card. Rich now we are using SPI bus on
Lyre prototype and seems working ok, but we don't have audio working so
we can't test if is ok the SPI bus.

I understand now the question of need to have an internal flash memory
for old Rockbox bootloader + Rockbox firmware + saved files, but we want
an SD card for music, since it will boost the music sharing, and we want
to help people sharing the music (I mean with Creative Commons license
and the recorded by users).

Thank you :-)

Qui, 2009-04-09 às 09:23 -0400, uhmgawa escreveu:
> Casainho wrote:
> > Hello :-)
> >
> > We are working on Lyre project, a Free/Open hardware audio player
> > (DAP) and recorder, for use with RockBox firmware.
> >
> > We want to boot our ARM9 from SD Card, but we would like to avoid the
> > need to pay royalties for using the SD BUS for communicate with card.
> >
> > Does anyone knows if this ids true?
> >
> >> I think the royalties for the SD Bus are payed by the IC
> >> manufacturer.
> >
> > Or the manufacturer should pay the royalties? in this case, us, before
> > selling the hardware? - we pretend to assembly and sell on Ebay...
> >
> IIRC the licensing kicks in at the point a manufacturer
> uses the SD logo to advertise their device as SD compliant.
> But IANAL and things may have changed since I last looked at
> this so you'll need to do some legwork to verify your legal
> obligations relative to your situation. Start here:
> If you are adding an SD host controller to your device (or
> paying for the same integrated into the SoC) it seems odd
> not to use the controller -- if for nothing else than to
> offload the CPU.
> That said you could get by without a controller at audio
> bit rates by talking to an SD card in SPI mode. This is
> bit serial and only yields 25% of the theoretical maximum
> bandwidth available in 4-bit SD mode. But it is cheap
> and more than sufficient to transfer audio data to/from
> the card. If you don't have a SPI controller you could
> even bit bang an interface assuming you have sufficient
> CPU bandwidth available.
Received on 2009-04-10

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