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Problems accessing port A in DSP56303

Started by Hernan Dario Herrera March 9, 2004
Hi,
Im working with the DSP56303 and Im having trouble when I send data to the
port A.
If I send, for example, $D12F, and I receive $D21F, or $C52D and I get $C61E.

In the same way, the address lines dont match the value I have set up, for
example: If I want to write something to the address $007850, in the 16 bits of
address lines I get $9403, that I think they are the lowest significant bits of
the 24 bit address, other case is: $0F0850 and I get $1A00 I don't know if the DSP in this process changes some bits or, maybe, I have not
configure something.

If someone has a proved code in assembly and can send it to me, I would thank.

See You. Thanks.

Hernan Herrera



Moin Hernan,

I assume you are referring to the external memory interface on Port A,
have you properly set the Adress Attribute Registers AAR3-0 ?
Note that according to Mot errata you should set all four to a valid
(dummy-) address range and SRAM type, and none of them should be set to
synchronous SRAM. BCR and also DCR, in case you use DRAM, must be set
prior to using Port A. Since you asked for code, here an example of
an initialisation I use: movep #$D00439,x:M_AAR1 ; select Flash as in Mot Bootstrap, enable
also X/Y access
movep #$C00431,x:M_AAR0 ; select USB Chip on $C00000..$CFFFFF
movep #$AFBC31,x:M_AAR2 ; CV DAC on x:y:$AFB000...$AFBFFF ($DAC000
not possible here)
movep #$B00C31,x:M_AAR3 ; set AA3 to dummy address
movep #(WS_DEF<<16)|(WS_DEF<<13)|(WS_DEF<<10)|(WS_FLASH<<5)|WS_USB,x:M_BCR

Ciao,
Stefan

Hernan Dario Herrera wrote: > Hi,
> Im working with the DSP56303 and Im having trouble when I send data to the
port A.
> If I send, for example, $D12F, and I receive $D21F, or $C52D and I get $C61E.
>
> In the same way, the address lines dont match the value I have set up, for
example: If I want to write something to the address $007850, in the 16 bits of
address lines I get $9403, that I think they are the lowest significant bits of
the 24 bit address, other case is: $0F0850 and I get $1A00
>
>
> I don't know if the DSP in this process changes some bits or, maybe, I have
not configure something.
>
> If someone has a proved code in assembly and can send it to me, I would thank.
>
> See You. Thanks.
>
> Hernan Herrera