The CGS28 is a "core" module for sequencer type work. In its simplest form, it can be used to select between different signal or CV sources. With a simple pot-based front end and an external clocking LFO, it can be made to function as a regular sequencer. It is also possible to sequence between constant and modulated signals, for example, to enable vibrato to be placed on every fourth note. It can also count down, under external control, allowing for some interesting patterns to be produced with the addition of an extra clocking LFO.
CGS28 Datasheet and Build Guide