I use the step sequencer for that (driving an instance of TTS-1). Better than the metronome, especially if you're working in something other than 4/4. Whenever I come up with a nice sequence for jamming or working up progressions, I save it as a step sequencer preset for future re-use. Years ago I'd have used a drum machine for that, but the step sequencer is way easier to program than a drum machine.
No need to un-check the stop-at-end option; either play the sequence as a loop or stretch out the clip to the desired length of your song.
But yes, you will need to create a MIDI track for this to work. But you don't need to put anything in it.