[En-Nut-Discussion] Ethernut 3 hardware points: RAM on expansion port and SD card
colin.chaballier at mt2.fr
Tue Aug 4 18:16:49 CEST 2009
Thanks for the point. At which speed did you run the address/data buses
? I don't have a clear idea on the latency introduced by the cpld.
Any more experiences on the use of the expansion port for external RAM ?
> Message: 1
> Date: Sun, 02 Aug 2009 17:50:03 +0200
> From: Ulrich Prinz <uprinz2 at netscape.net>
> Subject: Re: [En-Nut-Discussion] Ethernut 3 hardware points: RAM on
> expansion port and SD card
> To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
> Message-ID: <4A75B5AB.3080301 at netscape.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Hi Colin,
> I had used the external RAM on Ethernut 3.0e and other SAM7 based
> Applications without any problem. Just keep an eye on timing and correct
> The power-glitch while handling any hotswap device is a problem that can
> be worked around by installing a 100nf and a 1uF capacitor as close as
> possible to the vcc/gnd of the socket. This is a workaround as the real
> solution should be to design in a slot controller. I.e. a chip that does
> bus connection/disconnection including power up / power down of the cards.
> Best regards, Ulrich
> Colin Chaballier wrote:
>> As part of the integration of the Ethernut3 in a new design, I'm looking
>> at the feasibility to add external RAM through the expansion connector.
>> Do you have any feedback experience on connecting RAM through the
>> "configurable address bus" on this board ?
>> Apart the 16bit address bus limitation, should be there any issues
>> working on the address/data buses through the CPLD logic (latency
>> control for example) ?
>> My second point is about the SD Card support. In the Ethernut3
>> documentation it is reported that there should be a power line glitch
>> problem when inserting SD card of more than 2GB. Is this problem has
>> been definitely solved ? Or could we expect later issues when using
>> large capacity SD cards ?
>> Thanks for your answers.
>> Best regards,
> End of En-Nut-Discussion Digest, Vol 70, Issue 3
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