In an embodiment, a system on a chip (SOC) comprises a semiconductor die on which circuitry is formed, wherein the circuitry comprises a memory controller circuit and a plurality of networks formed from a plurality of individual network component circuits. The memory controller includes a PIO message control circuit that is configured to receive PIO messages addressed to individual network component circuits and determine whether to send the PIO messages to the individual network component circuits based on determine whether previous PIO messages are pending for the individual network component circuits. The PIO message control circuit is configured to delay a first PIO message at the PIO message control circuit in response to determining that previous PIO message is pending for the addressee of the first PIO message.