How to synchronize the DAC and ADC?

[escher]

I'm trying to do some signal processing on a steady-state cosine signal emitted by the DAC (whose memory buffer is fed using the I2S driver). I hence need to synchronize my reading from the ADC with the DAC signal so that I can calculate phase difference.

Is there a way to synchronize the DAC and ADC such that I can do this? The I2S DAC/ADC example shows how to read a buffer with the ADC and output a buffer with the DAC sequentially, but I would like to do that at the same time.

I note that many dedicated ADC chips have a sync clock input (so that multiple ADCs may be synchronized) - do the ESP32 DACs and ADCs have this? I haven't seen it mentioned in the API.