Hi to all,
some people seem to be interested to run the DAC1 of the codec on the EZlite-21369 with a sample rate of 192kHz without external clocks.
Here is an example code, based on an talktru from AD. The code is an DDS with 57kHz sine-wave output, the ADC of the codec runs with 96kHz, these samples are not used, the DAC1 runs with 192kHz and outputs the sine-wave.
CLK and FS for the DAC and the SPORT1 are generated by the PCGA and synchronized with the FS of the ADC. Because the CLK-divider is in bypass-mode, it is impossible to shift the falling edge of the CLK to the falling edge of the FS by the phase register (necessary for I2S-mode).
Therefore, the CLK for the DAC and SPORT1 must be inverted. This is done by the pinbuffer of DAIP20, see SRU-initialisation.
Before running the code, position 4 of SW7 must be switched OFF to disconnect the PB4 from DAIP20-pin.This causes the power-on-self-test of the board to fail. A 10k resistor between DAIP20 and GND solves this problem, but the code also runs if the POST is failing, see PB4 switch discussion.