When operating in Single channel mode, if you change the channel that is being converted on, how many conversions will it take for the channel to change?
There is a latency of 2-3 conversion cycles between changing the channel via the DRP write, and seeing the XADC output the conversion of the new channel.
For Single channel mode, a write to the channel bits will only take effect on the falling edge of busy.
This means the conversion after the write will convert the original channel selection and then latch the new channel.
The next conversion will still convert the original channel while acquiring the new channel.
The next conversion will be of the new selection.
You can change the channel every cycle as long as you account for the fact that the outputs will have a pipelined delay.
The CHANNEL output is present so that you can see what the last conversion channel was and what data output on the DRP will be.