To allow for reference current settings per multi-bit link (or alternatively, per apparatus), approaches for implementing closed-loop Tx swing control based on monitoring of a dummy circuit is provided herein. In accordance with some embodiments, provided is a dummy bit-link circuit to model operable bit-links in a multi-bit link, where each bit link has a transmitter with an adjustable swing level. Also provided is a reference generator circuit to control the transmitter swing levels based on test data driven through the dummy bit-link.