[TDA4VM] About AUDIO CLOCK

Manwoo Kim

Other Parts Discussed in Thread: TDA4VM

Hi,

I have a question about TDA4VM's AUDIO CLOCK.

In EVM schematic, There is crystal(Ref. Y1) for audio clock. When I check the crystal in EVM schematic, this is not working.

Is it correct? Does TDA4VM not support pin P29 and pin P27? Is it default state of the released TDA4VM?

If I connect crystal to pin P29 and pin P27, does it not working?

Please give me a answer!

Thanks,

Manwoo Kim

over 5 years ago

0 Stanislav Stilyanov over 5 years ago

TI__Genius 17650 points

Hi Manwoo Kim,

Crystal on OSC1 pins, P29 and P27 will work. It is not mandatory however, clocks to MCASP can be fed trough AUDIO_EXT_REFCLK pins, if desired.

Regards,

Stan

0 Manwoo Kim over 5 years ago in reply to Stanislav Stilyanov

Intellectual 565 points

Hi, Stan!

Thanks for your kind reply!

What's mean 'will work'? Does it mean that is it not working now? When I checked our EVM board, it doesn't work.

Is the working state normal on EVM board now?

Thanks,

Manwoo Kim

0 Stanislav Stilyanov over 5 years ago in reply to Manwoo Kim

TI__Genius 17650 points

What's mean 'will work'?

--> You mentioned in your earlier post "If I connect crystal to pin P29 and pin P27, does it not working?". I thought there is no crystal mounted.

0 Manwoo Kim over 5 years ago in reply to Stanislav Stilyanov

Intellectual 565 points

So, does crystal of EVM board work?

Could you please check the crystal of EVM board?

0 Stanislav Stilyanov over 5 years ago in reply to Manwoo Kim

TI__Genius 17650 points

Manwoo Kim,

Please use a suitable oscilloscope with a high impedance probe. Measure for oscillations on R77 (XO) pin. If you see oscillations at 22.5792 MHz, even with low amplitude, then the oscillator is operational.

However, it is possible your oscilloscope (or probe) introduce so low impedance, so that oscillator stops oscillations.

In this case, you can route (via software) the OSC1 clock to OBSCLK0 (observation clock output). Select this feature behind pin V5 (TIMER_IO1) in CTRLMMR_PADCONFIG143 register. Then choose OSC1 clock via the CTRLMMR_OBSCLK0_CTRL register. Then use the scope to monitor V5 pin.

Regards,

Stan

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[TDA4VM] About AUDIO CLOCK