DM8148 Auxiliary Clock

sivakumar thirumoorthy

Hi,

In my design, i am using DM8148 DaVinci processor. For reference, i used Mistral reference schematic (MS_TI_DM814x_BB_REVD_SCH).

TI recommending 20MHz clock for both Device clock and Auxiliary clock.

But in reference schematic they have used 22.579MHz auxiliary clock.

Why they have used that clock?

Is TI suggesting to use that 22.579MHz clock rate?

Regards,

Sivakumar

over 12 years ago

0 Vladimir-XID over 12 years ago

TI__Genius 11470 points

Hello Sivakumar,

Please, check the device TRM:

"2.3.10 Device Clocking from External Sources"

"Figure 2-15. Device Clocking External Clock Sources"

Thank you.

Vladimir

0 sivakumar thirumoorthy over 12 years ago in reply to Vladimir-XID

Prodigy 110 points

Hi Vladimir,

I didn't get the document what you have mentioned.

I have the document SPRUGZ8.

kindly provide the Literature Number.

Thanks & Regards,

Sivakumar

0 Vladimir-XID over 12 years ago in reply to sivakumar thirumoorthy

TI__Genius 11470 points

This has to be the same. It is the Technical Reference Manual of DM814x.

Vladimir

0 sivakumar thirumoorthy over 12 years ago in reply to Vladimir-XID

Prodigy 110 points

There is no information regards why they are using 22.579MHz and for which application.

Regards,

Sivakumar

0 Vladimir-XID over 12 years ago in reply to sivakumar thirumoorthy

TI__Genius 11470 points

In the same TRM, please check pages 453, 458 and 467.

In that case, apparently the AUXOSC is user defined in the range 20-30MHz in order to be utilized for video and/or audio PLLs depending on the application. "For instance, if a precise audio reference clock is needed, AUXOSC would provide this (e.g., 22.5792 for 44.1k audio)..."

Thank you.

Vladimir

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DM8148 Auxiliary Clock