Question about CV1800B hardware design - What is AUX0 resistor for?

[emeb]

The reason I had this question about the AUX0 pin is that it’s the only I2S MCLK output available on the CV1800B SoC and I wanted to make sure that re-using it as an I2S signal wouldn’t interfere with whatever was going on with R17. Having confirmed that it doesn’t seem to matter I tried it out as MCLK and was successful. More detail on that here:

MilkV Duo external I2S input

A bit more followup on the I2S situation. One of the big issues getting in the way of using ordinary I2S codecs is that there didn’t seem to be an MCLK output for the codec to run off of. That forced me to look at some offbeat codecs that included a PLL to regenerate MCLK from the BCLK input and the only reasonably priced one I found also had pretty bad audio performance. This encouraged me to think harder and in the process I discovered that pin 25 on the CV1800B SoC (labeled AUX0) can actually…