Time synchronization is of prime importance in distributed industrial control systems and in automotive networks. The time stamps of events in a distributed control system should match with considerable accuracy to be able to correlate them together or for the control system to operate properly. Various time synchronization protocols are used on different networks which allow synchronization upto various accuracies. Precision Time Protocol or PTP or IEEE1588 is one such protocol which allows synchronization of an order of 1us with the master (most accurate) clock in the network. On local area Ethernet networks it is implemented in various ways most often in software. This method is inherently less accurate for timestamping which results in reduction of synchronization accuracy. Implementing a time stamp unit in hardware which generates time stamps as soon as the PTP packet arrives from the network allows more accurate time stamps and hence, better synchronization.
The precision time protocol IP designed at Faststream technologies implements the PTP on Ethernet networks and sends the packet to the MAC. Precise time stamping unit instantiated in the IP captures the time stamp as soon as the packet is received and decoded. The values of offset and delay required to correct the local slave clock are generated by the IP.