PCM3060 no data from ADC

Matthew Mucker

Other Parts Discussed in Thread: PCM3060

I'm prototyping a circuit using the PCM3060 and am getting quite frustrated. I've etched two boards and both exhibit the same symptoms. I have a 24.576MHz oscillator connected to pins 5 and 10 (BCK1 and BCK2). I have the MODE pin tied to ground through a 220K resistor, which puts the device in 3-wire parallel control. I have IFMD tied to 3.3V, which puts the ADC in MASTER mode.

In this configuration, I expect to see digital output from pin 3 (DOUT) and pin 4 (LRCK1). When I probe these pins with my 'scope, however, all I see is an attenuated 24.576MHz waveform.

This has happened on both boards that I've prototyped. The circuit I'm using is attached. (EAGLE seems to have mangled it somewhat but it should be legible.)

The only thing I can think of that I may have done wrong is to leave RST floating. Other than that, I'm stumped. Can anyone offer any insight as to what I may be doing wrong or what the solution could be?

Schematic: 2388.analog_section4.pdf

over 13 years ago

0 Michael Gambrill over 13 years ago

TI__Mastermind 21265 points

Hello Matt,

I will look into this for you. Give me some time to review your circuit and the PCM3060 and I will get back to you.

-Mike

0 Michael Gambrill over 13 years ago

TI__Mastermind 21265 points

Matt,

I'm sorry about just getting back to this. One thing I noticed after review your setup and the PCM3060 datasheet was your use of BCK1/2 as inputs while in master mode. On page 19 it states:

"In master mode, BCK1/2 and LRCK1/2 are outputs from the PCM3060. BCK1/2 and LRCK1/2 are generated by the PCM3060 from SCKI1/2, and BCK1/2 is fixed at 64 f

S."

0 Matthew Mucker over 13 years ago in reply to Michael Gambrill

Prodigy 80 points

*Facepalm!*

Thanks, Michael! I don't know how I swapped the BCK and SCK signals, but that certainly explains the problem I'm having.

Darnit, I really hate it when I advertise such a boneheaded move publicly. On the other hand, I'd rather be embarrassed than perpetually frustrated by a circuit that won't work the way I think it should. Hopefully I haven't damaged the chip and a little greenwire will fix things up.

0 Don Dapkus over 13 years ago in reply to Matthew Mucker

TI__Guru**** 189399 points

Matthew,

You can't use green wire, you must use blue wire!!!

-d2

0 Michael Gambrill over 13 years ago in reply to Don Dapkus

TI__Mastermind 21265 points

A maize and blue wire would be better.

0 Matthew Mucker over 13 years ago in reply to Michael Gambrill

Prodigy 80 points

I fixed the wiring error on my board (I used silver colored, uninsulated wire) but it appears I damaged the chip by driving the outputs. (Go figure.)

I replaced the PCM3060 and now it's generating BCLK and LRCLK as I expect. Unfortunately I still don't see anything on the DOUT pin. I haven't spent much time debugging the board with the new chip on it so I'm still holding out hope that I can convince this system to work for me. I'll have a good long sit-down with the datasheet to see what I might be missing. I just wanted to close the loop and offer thanks for everyone's help.

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PCM3060 no data from ADC