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From: Guy Eschemann on 14 Apr 2010 15:28
On Apr 14, 3:31 pm, "bluds"
<vtescandell(a)n_o_s_p_a_m.n_o_s_p_a_m.gmail.com> wrote:
> >On Apr 14, 6:23=A0am, glen herrmannsfeldt <g...(a)ugcs.caltech.edu> wrote:
> >> bluds <vtescandell(a)n_o_s_p_a_m.n_o_s_p_a_m.gmail.com> wrote:
>
> >> (snip, I wrote)
>
> >> >>One of the modes of CF looks exactly like an IDE disk driver.
> >> >>A CF to IDE converter can be made with pretty much no logic.
> >> >>I believe there is also a mode that looks like a RAM.
> >> > What do you refer when you talk about modes??
>
> >> You can use CF cards in different ways. =A0It seems that newer
> >> ones even have an SATA mode. =A0
>
> >> > Do you know anywhere where i can find information about how to access
> t=
> >he
> >> > compact, because i never used a FPGA and i don't know how to access a
> >> > remote device.
>
> >>http://www.compactflash.org/
>
> >> Newer versions of the standard seem to cost $100.00, though
> >> it says that students can get a copy free. =A0I thought that
> >> older versions were available free, but I don't see that now.
>
> >> I believe that you can get some information from CF card
> >> manufacturers, too.
>
> >> -- glen
>
> >Most of the modes are selected by strapping resistors.  Make
> >sure your hardware is wired to support the mode you want to use.
> >Memory mode would be simplest, but the IDE mode often allows
> >faster access, at least for writing large blocks of memory.
>
> >When you say "the Compact Flash" do you mean one on an existing
> >board?  Or is this a new hardware design?
>
> >Regards
> >Gabor
>
> I just bought the xilinx XUPV5-LX110T board, which mainly is a Xilinx ML505
> with a more powerful virtex 5 FPGA.
>
> It is possible to connect to this board a compact flash, this compact can
> be used to load designs to the FPGA.
>
> My objective is to use the compact flash as my hard this. This is going to
> be a special hard disk, because i don't need it has any format. I only need
> to read the bits that are stored there.
>
> The problem is have is that i don't know how can I access the compact from
> the FPGA. I have never used FPGA's, so i have no idea how external devices
> can be accessed.
>
> Somebody told me that, as the compact cannot be read bitwise (i think he
> told me that is read blockwise) i thought about reading the whole content
> from it and copy it to memory, and from there read it as i want.
>
> The idea is to feed the design with this information.
>
> My main problem, is that i'm a newbie with FPGA and i don't have any idea
> how can i do this. I tried to find examples, or information about how to
> manage all this but i didn't succeed.
>
> All the information that anybody can provide is really welcome :D
>
> Thanks    
>
> ---------------------------------------        
> Posted throughhttp://www.FPGARelated.com

I'm afraid that you won't be able to use the CompactFlash card in
"raw" mode. On the board you mentionned, the CF card is connected to
the FPGA via a System ACE chip, which expects a FAT16-formatted card
(see the user guide).

Cheers,
Guy.

From: whygee on 14 Apr 2010 15:37
glen herrmannsfeldt wrote:
> In addition, CF has the 8 bit transfer mode that was originally
> part of IDE/ATA but somehow forgotten along the way. Somewhat
> easier for some systems than 16 bit mode.
I'll have to check but even though I have seen interfaces
using a 8-bit datapath (8255-based), this works only for commands.
For data blocks, it wastes the higher byte of each transfer
so you 512-byte sectors shrink to 256-byte chunks.

Now, if you find a counter-example, i'll be glad :-)

regards,
> -- glen
yg
--
http://ygdes.com / http://yasep.org
From: glen herrmannsfeldt on 14 Apr 2010 16:20
whygee <yg(a)yg.yg> wrote:
> glen herrmannsfeldt wrote:
>> In addition, CF has the 8 bit transfer mode that was originally
>> part of IDE/ATA but somehow forgotten along the way. Somewhat
>> easier for some systems than 16 bit mode.
> I'll have to check but even though I have seen interfaces
> using a 8-bit datapath (8255-based), this works only for commands.
> For data blocks, it wastes the higher byte of each transfer
> so you 512-byte sectors shrink to 256-byte chunks.

> Now, if you find a counter-example, i'll be glad :-)

As I understand it, CF has both 8 and 16 bit modes, so you
don't need an extra latch, or to waste half the data block.

That is, it has the mode that IDE disks were supposed to have,
but almost none implement.

-- glen
From: Kappa on 16 Apr 2010 08:26
Hi,

If you change idea on CP and you decide to use USB storage, this chip
is very helpfull:

http://www.vinculum.com/

Manage USB drive FAT12/FAT16/FAT32, read/write file (well binary) from
UART.

Kappasm
From: bluds on 19 Apr 2010 11:11
Thanks to everybody for your incredible help.

I've been reading more about my board, and Guy is right. It seems that the
only way to work with the compact is using the systemACE.

Working with systemACE seems much more easier than programming the entire
driver to use the compact. You only have to take care of reading and
writing some registers to configure and use the systemACE.

Reading the available documentation i found one question that i couldn't
answer and is where the information that is going to be read or write from
the compact is saved inside the fpga.

Anybody has any idea?

Thanks

-- bluds

---------------------------------------
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