Forums

invert the DX-pin on McBSP ?

Started by olaf636 September 9, 2003
the voltage on the c6711-dx-pin was approx. 3,3v, changes to zero and
then starts the data-transfer.
but now on the c6713-dsk, it`s always zero, but the DR-pin of the
c6713-dsk`s is always 3,3v like the c6711, so when i connect these
pins, the voltage is approx. 1,7v with no changing during the
data-transfer.

does anybody know how i can change the dr- or dx-pin-voltage ?

can`t find any settings, "actice high/low" is only for the framing... sincerely,

olaf



Olaf,
 
Something is wrong! Do not leave those pins connected like that.  Your symptoms imply that one pin is "driving low" and the other pin is "driving high" - creating a voltage divider effect.  Double check your pins and config.
 
Which specific pins are you connected to??\
 
mikedunn

olaf636 <c...@t-online.de> wrote:
the voltage on the c6711-dx-pin was approx. 3,3v, changes to zero and
then starts the data-transfer.
but now on the c6713-dsk, it`s always zero, but the DR-pin of the
c6713-dsk`s is always 3,3v like the c6711, so when i connect these
pins, the voltage is approx. 1,7v with no changing during the
data-transfer.

does anybody know how i can change the dr- or dx-pin-voltage ?

can`t find any settings, "actice high/low" is only for the framing...sincerely,

olaf
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> Something is wrong! Do not leave those pins connected like that.
Your symptoms imply that one pin is "driving low" and the other pin is
"driving high" - creating a voltage divider effect. Double check your
pins and config.
>
> Which specific pins are you connected to??\
>
> mikedunn
dear mike,

i have connected the DX0-pin from one dsk to the DR-pin from another dsk.
on the master-dsp is the DX-pin on 300mV and the DR-pin on 3,1V like
the slave-DR-pin.

but i believe that the McBSPs are not initialised correctly, so
perhabs they are still "connected" to the onboard AIC23-codec, because
when i write the code for the McBSP1 on the master-dsp i see nothing
on the scope....no clock, no frame, no data and DX/DR-pins are
low...no 300mV, just 0V......