Synchronize internal DAC to I2S on STM32F4
I was not able to figure that out in the STM chips. 

I had to solve a very similar problem to yours (phase-locked DMA transfers). I had to move to the NXP Kinetis chip to do it. The Kinetis has a few 

 - DMA channels where requests can be gated by the
     -&gt; Programmable Interrupt timer, 
         -&gt;which can also trigger the programmable delay block, 
             -&gt;which can trigger the flexible timer module, 
                 -&gt;which can be configured to start the DAC conversion. 


It was a "clever" (brittle, hardware-dependent) solution. But I needed it, and it worked.