This repository contains a toy (illustrative) EtherCAT master implementation in C, demonstrating:

• A slave state machine (INIT -> PRE-OP -> SAFE-OP -> OP) with mailbox transactions to actually set AL Control and poll AL Status.
• Distributed Clocks (DC) logic (reading offset from one register, writing correction).
• Dynamic datagram queue (no fixed 256-byte limit) for partial batching of EtherCAT frames.
• SoE (SERCOS over EtherCAT) stubs (soe-read, soe-write).
• FoE (File over EtherCAT) stubs (foe-req), using a single-block approach.
• ESI parsing + minimal ring scanning to discover slaves and match them to ESI data.
• A POSIX-based event loop for DC and frame events.
• A CLI with commands like:
  • read, write (basic FPRD/FPWR)
  • soe-read, soe-write
  • foe-req
  • scan-esi (parse ESI files and discover slaves)
  • slave-state <idx> <state> (requests mailbox transition)
  • stop (shuts down)

Disclaimer: This is a toy or demonstrative EtherCAT master, not production-ready. Real systems require more robust ring scanning, full mailbox usage, multi-slave DC synchronization, PDO configuration, and advanced SoE/FoE chunking/ack. Use this code as a learning or prototype reference.

• ul_ecat_master.h: Single public header with all API declarations.
• ul_ecat_master.c: Implements everything in one file:
  • Master lifecycle (init/shutdown, RT thread).
  • DC logic.
  • Dynamic datagram queue + partial batching.
  • Slave DB and ESI matching.
  • SoE / FoE stubs.
  • Event loop.
  • CLI (read/write/soe-read/scan-esi, etc.).
• ul_ecat_tool.c: Minimal main() that calls ul_ecat_app_execute(argc, argv).
• CMakeLists.txt: Example build script for CMake.

1. Install a C compiler and CMake (>= 3.0).

2. Clone or copy these files into a folder named ecat_project/.

3. In a shell:

   cd ecat_project mkdir build cd build cmake .. make

4. This produces ecatTool under build/.

From build/:

./ecatTool [args...]

• scan-esi <file1.xml> <file2.xml> ... null Parses the ESI files, scans a minimal ring (fake 2 slaves), matches them with the ESI data, and prints results.

• slave-state <idx> <state_dec> Requests the mailbox transition from current state to the desired one (INIT=1, PRE-OP=2, SAFE-OP=4, OP=8). Writes AL Control, polls AL Status.

• read <addr_hex> <len> Queues a read command (FPRD) to that EtherCAT address.

• write <addr_hex> <value_hex> [size=4] Queues a write (FPWR).

• soe-read <drive_no_dec> <idn_hex> Minimal SoE read request.

• soe-write <drive_no_dec> <idn_hex> <val_hex> Minimal SoE write request.

• foe-req <opcode_hex> <size_dec> [pw_hex=0] Sends a single-block FoE request with optional password.

• stop Shuts down the master: stops the RT thread, closes raw socket.

• The code posts DC events or frame arrivals into a POSIX event queue but does not automatically call ul_ecat_eventloop_run().

• If you want real-time event callback usage, do something like:

  ul_ecat_register_dc_callback(my_dc_handler); ul_ecat_register_frame_callback(my_frame_handler); ul_ecat_eventloop_run(); // Blocks until ul_ecat_eventloop_stop()

• This ensures user code executes in a single event-loop context, not in the RT thread.

• No advanced mailbox error handling, multiple CoE or SoE transactions, or multi-slave DC.
• State transitions are partial stubs with short polling loops. Real usage might parse actual read results.
• SoE / FoE are single-block stubs without chunking/ack.
• This is a learning prototype, not a production solution.