Can’t tell you the specifics on the midi in/out now but I’ll sit down with the Digitakt tonight and figure it if no one has chimed in by then. Might take me till tomorrow.
Right now there is no song mode, no preprogrammed and saved pattern chains.
You can however change how many steps a pattern plays when chained. This is in the secondary scale menu. This includes extending the steps to 2, 3, 4 times beyond 64 steps. Basically how many times do you want the pattern to repeat before going to the next pattern.
For me right now, typically patterns 1 & 8, 2 & 9, etc are copies. That way I can chain them for slight variations on pattern length. Leaving one pattern blank and tagging it to the end of song will let you know to get to the Digitakt and queue your next chain.
I’d like to see at least one saved pattern chain per bank or an internal midi loop to control the program changes with.