The optimal use of bandwidth requires that TX local bus data can be written at a rate faster than it can be delivered on the serial interface. This means that there must be backpressure, or flow-control, on the TX segmented LBUS. The signals used to implement backpressure are tx_rdyout and tx_ovfout . These signals are common for all segments. When responding to backpressure during a clock cycle, none of the tx_enain S can be active.