The ONESHOT chip is a One-Shot Event Generator. It creates interesting unipolar modulation waveforms made from a single ”ping”. You can alter the shape and speed of the ping, and also add decaying echos to it, with separate Delay and Repeats controls. This lets you easily generate interesting and unusual one-off modulation waveforms. It makes things that sounds like a ball bouncing on the floor, or a single hit with echoes, or a stick being dragged across a washboard.
As such, it exists somewhere in the area between an envelope generator and an LFO.
The datasheet includes the pinout diagram and application circuit.