Dave ,
Thank you for your reply.
It is a board with CPU, SDRAM and also flash IC and some  other parts ( Yes=
, that is a Linux=20
enbeded device).
I would like to load some data into flash( for example to change a loader i=
n flash)
What would you suggest, if I want to load data into IC FLASH?
Thanks


> jana1972@centrum.cz wrote:
> > E.g. I would like to write some  new data into IC flash memory.
> > So I was thinking about using JTAG. But for that I would need to know S=
PI
> > address.=20
>=20
> Well, that depends. If the flash memory has a JTAG interface and is wired=
 into
> the board's JTAG chain (this is common with flash memories used with FPGA=
s,
> less common on those used with MCUs), then no, loading new data does NOT
> involve the SPI interface at all.
>=20
> On the other hand, if you're talking about using a JTAG interface on the
> processor to access the flash memory via SPI, that's very difficult to do
> directly.
>=20
> It is at least theoretically possible to bit-bang an SPI interface using =
JTAG
> commands, but this would be very slow, and tricky to develop.
>=20
> The usual approach in this situation is to use the JTAG interface to load
> the data into the processor's memory (RAM) along with a small program tha=
t
> executes on the processor and transfers the data to the SPI device. In or=
der
> to develop that program, you'd still need to figure out how the processor
> accesses the memory (which SPI interface and which chip select).
>=20
> For example, this is exactly how it's done on all Analog Devices EZ-KITs,
> which are evaluation/prototyping boards for their various DSP chips.
>=20
> > Do I understand well, that the only way how to find out the SPI address=
 is
> > to debug the driver or BIOS of that device?
>=20
> That's one way. As I said, if this memory is used to boot the processor, =
you
> can also look in the processor's documentation.
>=20
> > And/or Isn't there any other way how to write data into the flash of th=
at
> > Linux embeded device?
>=20
> I really couldn't say -- it depends on the design of the board. If this i=
s
> a commercial board, can you tell us what it is? Then we'd have a chance o=
f
> tracking down some documentation on it.
>=20
> -- Dave Tweed
> --=20
> http://www.piclist.com PIC/SX FAQ & list archive
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> http://mailman.mit.edu/mailman/listinfo/piclist


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