Teensy4 with PCM5100 i2sslave, no sound

[M4ngu]

Hi people, just got the boards for a project with Teensy4, the DAC for the audio part is a PCM5100, which should work as i2sslave device but I get no sound,
I've tested with a few examples from the audio library (replacing the output device with 'AudioOutputI2Sslave'
the pins appears to be chosen correctly,

the circuit of the DAC has the FMT pin to ground, so the audio format selected is i2s.

My question is if there's something else I should add to the code to use that device, apart of the code generated by the audio design tool and the 'AudioMemory(xx);' in the setup.
thanks in advance
http://www.ti.com/lit/ds/symlink/pcm5100a.pdf

 

[Theremingenieur]

There is no reason to make the audio output a slave because then, the Teensy would expect getting the clocks from the external device but your DAC does not provide these. This DAC is already a slave which makes that the Teensy must be the master.

If you had used a cheap 8$ logic analyzer, you would have seen that the Teensy does not output any I2S clocks when in slave mode.

 

[M4ngu]

ok I misunderstood the fact that the DAC does not need a clock with being a master i2s device,

'The integrated PLL on the device removes the requirement for a system clock (commonly known as master clock), allowing a 3-wire I2S connection and reducing system EMI.'

actually working as a regular i2s output,
thanks!

 

[Theremingenieur]

The PCM5100 series generates itself the master clock from the incoming bit clock. But that latter has to be provided, that's why the Teensy has to be the master.