I'm working with a ADAU1701 with an interface to a microcontroller and numerous other system components. The uC needs to do some processing with data generated by the SigmaDSP, and the processing should be done at a 1 kHz rate synchronized to the 48k DSP sample rate. So far, I can successfully interrupt the uC with a GP output from the SigmaDSP and read the data I need with a DSP Readback cell. The GP output from the DSP is generated by a stopwatch, however I am finding that it doesn't seem to be synchronized to the analog output. I observed this by triggering a scope on this pulse train while displaying the analog sine output (the analog out jitters/drifts with respect to the pulses).
Here's the graph. I was expecting that the GPIO_1 output pulse would be in sync with the DAC0 output signal.
Is there something I'm not understanding about this, or is there a better way to sync the GPIO with the sample rate?