CSRA64215 > PCM5102A - I2S - No sound

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This is not my first electronics project, however it is my first digital audio project. I don´t get it to work, I´m not sure what I missed.

Having the two modules hooked up to what I could find to be correct way, I don´t get more than clicking and buzzing sounds when trying to play music from the phone.

I´ve read a few post about it in this thread:
CSR8645 Bluetooth 4.0 AAC APT-X Module / Baseboard


As I understand a basic I2S setup looks like this:


I tried it like that + having the SPI PCM connected ground (supposedly enabling I2S) + having a 10k resistor between 3,3 v and MFB (Wake up?)

Any ideas what I´m missing?
 
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Yes, that might be the problem. The board has a pin called 1V8 which very well measures 1,8v.

It tried it with the only level shifter I had lying around, a TXB0104, but it didn´t make a difference.

The board you have must have a level shifter then dosen´t it? Maybe the speed of mine is insufficient
 
Do you have the schematic for the PCM5102A board? I cannot tell by looking at if you have pull-ups on the XSMT pin and a pull down on FMT to set the device into I2S mode.

Table 11 in the PCM5102A PDS shows the required sample/bck speeds required for the PCM's PLL to function.

Is there a difference in the bluetooth board between the pin labeled MOSI and the one labeled 'PCM MOSI'?
 
If possible, scope the i2s pins to verify IO voltage.

Your module 1v8 pin is most likely the digital power rail. You need to find the chip pin for VDD_PADS_1 and trace to where it meets the power source, dependent on how it is supplied (regulated 1.8v or resistor network from 3.3v) cut or modify so the vdd_pads_1 receives 3.3v because that's what the digital audio IO pins reference from.

Finding the in-module circuit schematic for CSRA 64215 modules is very difficult, another I previously inspected had a 0R resistor and unpopulated spot for selection of this voltage. Perhaps your has similar configuration?
 
I don't have the schematics for the PCM5102A. I tried to add resistors as described but with no luck.

I read that the TXB0104 actually is recommended for I2S. (I2S level shifter - Voltage Translation / Level Shifters Forum - Voltage Translation / Level Shifters - TI E2E Community)

I don´t have a oscilloscope unfortunately so I´m not sure how I can scope the signals. I did try to measure it with the multimeter though. When the music is stopped the I2S pins all read 0 v. When I start the music the pins reads like this:
MISO 0,48 v
CSB 0,88 v
CLK 0,88 v

So I guess there seems to be some kind of signal.


The board sure have a 0 ohm resistor exactly as you described!

 
Your wiring diagram is wrong. You have to connect 3.3v to VCC on the DAC module and not to the 3.3v. Also put a 10k resistor between SPI_PCM and GND. No need for resistor between MFB and 3.3v. Then it should work. Also have in mind that left-justified data format should be selected on the DAC as CSRA64215 by default sends the data in this format, so you will probably have to short 3.3v with the FMT pin, but check if it's not already shorted as I haven't used this particular board before.
 
Tried to connect it as described. Still no luck, I don't get anything other than noise. With the levelshifter I at least get a crackling noise that follow the music I'm trying to play.

Feel a little bit limited in my troubleshooting without a scope. I guess I need to invest in one.

I ordered a Converter Board module just in case I don't get this one to work.
 
Finally got myself a oscilloscope. I guess it's a must when working on projects like this.

Found out that the CRS module sure have 1.8v output logic. Seems like the level shifter is not capable to replicate the signal:


CSR Clock signal - Green | Level shifter output - Yellow

I guess I need another level shifter to get this compo to work?
 
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