partis
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Re: SD Card Access

Mon Nov 14, 2011 11:09 pm

Hi all

I asked yesterday about GPU access documentation - if only simple read/write to a framebuffer after 'something' sets up said framebuffer.

Further to this, is the SD card accessed via the GPU or the CPU? The reason for asking is the implication of the GPU having control over the SD card due to the booting mechanism (or have both devices have some form of shared access?).

Is the method SD card access going to be made public (even if it requires bit banged IO)?

Cheers

Gary Partis
Gary Partis

asb
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Re: SD Card Access

Mon Nov 14, 2011 11:16 pm

My understanding is SD access is all through GPLed kernel code.

Arreladd
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Re: SD Card Access

Mon Nov 14, 2011 11:25 pm

Another good question I have been wondering is, What is the max SD card size that the system can support? plus I have used an SD card adapter which takes to micro SD cards and turns them into 1 Standard SD Card. The adapter is pretty inexpensive and getting that and a couple of micro SD cards (best results are with 2 of the same kind/size) this usually is cheaper than buying the larger size standard SD card.

partis
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Re: SD Card Access

Mon Nov 14, 2011 11:44 pm

Hi asb

Quote from asb on November 14, 2011, 23:16
My understanding is SD access is all through GPLed kernel code.

Sorry, I didnt ask the question correctly...

Can the ARM CPU access the SD Card IO directly (ie. not thru the GPU) and will it be documented? This is external to Linux kernel, being that Linux would not be running on the platform.

Cheers

Gary
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Montekuri
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Re: SD Card Access

Mon Nov 14, 2011 11:51 pm

Quote from Arreladd on November 14, 2011, 23:25
Another good question I have been wondering is, What is the max SD card size that the system can support? ...
There are some topics about this question:
http://www.raspberrypi.org/for.....#038;t=167
http://www.raspberrypi.org/for.....#038;t=483
It seems to be 8Gb the maximum size, but I'm not sure.

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liz
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Re: SD Card Access

Mon Nov 14, 2011 11:53 pm

Quote from partis on November 14, 2011, 23:44
Hi asb

Quote from asb on November 14, 2011, 23:16
My understanding is SD access is all through GPLed kernel code.

Sorry, I didnt ask the question correctly...

Can the ARM CPU access the SD Card IO directly (ie. not thru the GPU) and will it be documented?


It does, and it will be documented. It's just an SDHCI peripheral. ;)
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MmmPi
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Re: SD Card Access

Tue Nov 15, 2011 1:01 am

Quote from Arreladd on November 14, 2011, 23:25
plus I have used an SD card adapter which takes to micro SD cards and turns them into 1 Standard SD Card. The adapter is pretty inexpensive and getting that and a couple of micro SD cards (best results are with 2 of the same kind/size) this usually is cheaper than buying the larger size standard SD card.

Two MicroSD to Standard SD adapter? I have never seen that. Do you have a link? I have only seen a Two MicroSD to Memory Stick adapter.
.

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