I can't see a dmamux source for bctu fifo2.
does it not exist? don't see that being mentioned anywhere in the data sheet.

i have two separate hw triggers for the bctu to start two separate conversion lists and store the results in a fifo and have a dma to move them over and then trigger the callback in the dma completion to use the adc data.
but cannot do this for the second fifo seemingly as there is not a source for the dma mux to do this with.