OK !!! hooray !!! Fixed the I2C communication for the CS4385 DAC using my trusty state of the art volt meter :)

I had used a pullup resistor to try to make to reset pin high that was too large.

not enough voltage to pass threshold on Reset pin to power up DAC !!!

I also added 2 x 4.7k pullups ro the I2C bus. the voltages where around the 3v mark which seamed a fraction too low.. now there nearer 4v when high.

I have no idea if thats the correct thing to do !

can't remember where i got my volt meter from, maybe a christmas cracker ?

I really need an Osciloscope, was looking at the Agilent 2000 series, but a lot of money for me really and not even sure I really would need something that powerful.. although the cheaper Rigol stuff looks like a strange toy !!!

. can anyone surgest what a good one would be for looking at multiple SPI I2C port communications etc ?

anyway, I have 8 channels of DAC volume control and theres no noise at all !! must have got the sepperate digital / analouge grounds right this time. Amazing :) :)

Think its time to order that 8 channel ADC and hook it up to the 8 channel TDM !!!

I'll tidy up the code and make a video of this DAC mixing a couple of I2S audio sources as soon as I get time..