Bit ordering for packetised serial data transmission on an integrated circuit

An on-chip integrated circuit interconnect uses a serialization technique to divide a transaction to be transmitted into a sequence of transmission packets which are serially transmitted over a narrower connection. The order in which bits of the transaction are allocated to transmission packets is selected such that higher priority bits required by a receiving slave device in order that it can commence processing the transaction are sent first. This reduces the latency of the system.