Hi,
we are facing a problem with TAS5756 in I2S master mode.
The MLCK is generated by two oscillators where each one can be switched on/off by a GPIO pin of TAS5756 depending on the sample rate.
In slave mode our design works without any problems. When switching over to master mode the amplifier part always stays quiet.
Our software driver seams to be working correct. We are able to switch the GPIO's and enable the clocks. The TAS5756 successfully drives the BCK and LRCK pins and the host starts to send audio via the data-out pin. When putting a scope on the DAC-OUT pins we can clearly see that an analog audio signal is coming out of the DAC part of TAS5756. Even hooked up an external amplifier to that pins and analog audio works just great.
The problem is that the amplifier part does not work when the DAC is in master mode. SPK-FAULT# and MUTE# pin are both pulled up to 3V3 through a 10K resistor.
Is there any internal control logic connect between the DAC and the amplifier part that could force the amp to stay in mute under certain circumstances?
Are there any register settings for this? For development of our driver we have used the register map of PCM514X since we couldn't find a specific one for the TAS5756. Is that okay?
Exactly the same board with same speakers and same power supply plays without any problems in slave mode.
In slave mode we can measure a voltage between GND and e.g. SPK1+ of about half the supply voltage while connected to a speaker and playing music.
In master mode we can only see SPK1+ pin raising about 0.5 volt above GND when music starts to play. Dropping back to zero a few seconds after music stops. So something seams to happen at least.
Any hints?
Really strange problem...
Best regards,
Philip.
