Detailed Description

Ethernet POWERLINK (EPSG) basic frame codec (DETWS_ENABLE_POWERLINK).

Ethernet POWERLINK is the EPSG real-time managed-node bus over raw L2 (ethertype 0x88AB, on the shipped services/rawl2). The Managing Node (MN) runs an isochronous cycle: it multicasts a SoC (Start of Cycle), unicasts a PReq (Poll Request) to each Controlled Node (CN), each CN answers with a PRes (Poll Response) carrying its process data, then an SoA (Start of Async) opens the async phase. Every EPL basic frame is:

[messageType : 1][destination node : 1][source node : 1][payload...]

This builds and parses those frames (the four cyclic message types + the node addressing), so the MN schedules the cycle and a CN answers with its PRes process image. Pure, zero heap, no stdlib, host-testable; the raw-L2 transmit + the isochronous timing (the preempting-task model) are the device step.

Definition in file powerlink.h.