How should I control an external VCXO with the DM8148?

Hans Rosenbrand

In our DM8148 application we want to use an off-chip VCXO to supply a low-jitter audio clock to the AUXOSC reference clock.
In the reference manual a "VIC inside TPPSS" is mentioned that will be used to control the VCXO.
To control the VCXO the "TPPSS VIC pin" could be used.
I can't find more information on this subject, for instance on what pin this feature is available an how to use it.
- any suggestions?

over 13 years ago

0 Viet Dinh over 13 years ago

TI__Genius 15310 points

Hi,

Please see this link for VCXO, http://e2e.ti.com/support/dsp/davinci_digital_media_processors/f/716/t/167040.aspx.

BR,

Viet

0 Hans Rosenbrand over 13 years ago

Prodigy 45 points

Hi Viet,

The topic you refer to is on a related subject, but does not explain how the "TPPSS VIC pin" is used to control an external VCXO, or where this pin is located.

Do you have any info on this?

BR, Hans

0 Viet Dinh over 13 years ago in reply to Hans Rosenbrand

TI__Genius 15310 points

Hi Hans,

We are currently don't support TPPSS in DM8148. Could you use other pin?

BR,

Viet

0 Hans Rosenbrand over 13 years ago in reply to Viet Dinh

Prodigy 45 points

Hi Viet,

Thanks for clearing this up.

I guess the best thing to do is to use one of the timer I/O's in PWM output mode to drive the VCXO.

BR, Hans

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How should I control an external VCXO with the DM8148?