Hello,
i am trying tu use a PCM2900C Audio Codec, we want to use it in a record player.
I created a test PCB according to datasheet Page 26/Figure 38.
I think i did a clean layout, short connections..., i checked all voltages of on Chip VR's, all seems ok.
Data lines 22R and 1,5k resistor versus D+ on data lines are present of course.
I always get message when connecting to USB under Windows "USB-device not recognized".
On XTO i can observe a 12MHz signal after connecting until this message pops up, then XTO goes high-
I tried to add additional decoupling cap's of 10nF in parallel to proposed 1uF/10uF caps without success.
Then i realized that coming near data lines with my finger 12 Mhz suddenly starts again, i tried to different test PCB's.
I experimented a little and found out that clock becomes stable, if i connect D* and D-Input with a 10K resistor, Data lines not connected to USB.
So one question:
Is XTAL oscillator supposed to run permanently , when powered? or is it disabled when USB fails connecting?
Datasheet does not show anyting about a internal disable/option in PCM2900C's functional diagram.
perhaps somone can help me
best regards
Wolfgang
