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dsp56303 flash boot

Started by Unknown December 16, 2003
hi. I'm trying to boot the dsp56303EVM but I don't understand why in
the evm manual says that the Flash memory is between $010000 and
$01ffff and in the dsp manual says that the flash bootstrap begins
at $D00000, so how does it execute the stand-alone code, if the code
is in anothe memory position??????

Regards,
Hernan D.



Hernan,

External memory on a 563xx DSP basically resides where ever you wish to
assign it. I'm not sure where in the 56303EVM manual you found a
location for flash as I didn't see any mention of it (unless you are
looking at a very old version of the manual). The address of any
external memory (SRAM, FLASH, etc.) is all dependent on the
configuration of the AARx registers. These registers allow you to map
external memory anywhere within the allowed external address space.

Now, during boot, the DSP will begin executing from $D00000 using AA1
as a chip select. This address appears as $0 on the external bus
because there are only 18 external address lines (A0-A17). Using the
EVM the internal starting address of $D00000 is really irrelevant
because the flash doesn't use more than 18 address lines and the DSP
will start loading bytes starting at FLASH address $0. Actual execution
of the stand alone code will start based on the starting address you've
included in the flash image (first 3 bytes are length of code and the
next 3 bytes are the starting address)...

--
dB --- wrote:
> hi. I'm trying to boot the dsp56303EVM but I don't understand why in
> the evm manual says that the Flash memory is between $010000 and
> $01ffff and in the dsp manual says that the flash bootstrap begins
> at $D00000, so how does it execute the stand-alone code, if the code
> is in anothe memory position??????
>
> Regards,
> Hernan D.


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