new Real time hat Added by InnoRoute IEEE1588 The PTP in the hardware is supported to the Raspberry Pi 4 located below. Based on Xilinx Artix-7 FPGA and a few Gigabit Ethernet PHY devices, the HAT acts as a network pass-through, adding accurate time stamps to egress (outgoing) packets, and stripping the time stamp from the ingress (incoming) side.
This kind of hardware time stamping involves instant rewriting of Ethernet packets using dedicated network hardware that the Raspberry Pi does not have. Yes, there are 1588 pure software stacks, but they can only achieve a resolution of 10 microseconds, unlike hardware methods that can achieve 10 nanoseconds.
1588 is widely used in telecommunications infrastructure, factory equipment control, and any application that needs to synchronize data consumption or data generation equipment. CERN extensively uses 1588 as its huge array of sensors and control equipment for all LHC experiments.this is White Rabbit System, Probably named after the time obsessive white rabbit when Alice in Wonderland became famous. So if you have a large installation and need precise control over when it happens, this may be exactly what you are looking for.
IEEE1588 PTP synchronization
The PTP client and the master device ping some messages back and forth between them, and the network timestamp records the precise moment when the data packet passes through the interface.These timestamps are the same as Local Bell. This is very important. Based on these measurements, the time of flight of the packet and the offset between the local clock and the remote clock can be calculated and corrected. In this way, each client node (hat) in the network will have the same concept of current time, so all network data packets flowing through the entire network can be synchronized.
The beauty of this system is that network switches, wiring, and all common infrastructure do not need to use 1588 or any other special functions, they only need to pass data packets, ideally with consistent delays.
Real-Time HAT configures its FPGA through SPI, Directly from Raspberry Pi OS, You can use multiple applications, just make changes on the command line. You can upload a custom bitstream, and if you want, you can use the HAT as a general-purpose FPGA development board. It is even stacked with the official PoE HAT, which makes it more useful when suspending the sensor at the end of a single wire.
Of course, if your needs are simpler and smaller than the Swiss city, you can crack the GPS clock source into the Raspberry Pi with a little welding, and then it’s fine.