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Command Station Internal Architecture

The DCC-EX Command Station code is layered to reduce overall complexity and improve the ability to add new features. The most important layers are:

  • DCC packet API (DCC.h)

    • provides loco speed/function and accessory control functions
    • maintains loco state and issues reminders

  • DCC realtime waveform generation (DCCWaveform.h, DCCRMT.h)

    • handles simultaneous track signal for multiuple tracks

  • Motor shield driver & track manager (MotorDriver.h, TrackManager.h)

    • handles shield specific pin numbers and current sensing

  • ACK Manager (DCCAck.h)

    • handles all program track access and tuning
    • provides high level multi-cv functions

  • Serial/Wifi/Ethernet input and output (SerialManager.h, Wifi*.h, EthernetInterface.h)

  • Command Distributor (CommandDistributor.h)

    • Manages multiple simultaneous input streams and broadcasts status changes

  • Command Parsing/execution (DCCEXParser.h + others)

    • recognizes commands and calls appropriate internal APIs

  • Exrail (EXRAIL*.h)

    • provides EXRAIL language functions
    • acts as single point of contact for almost every user-specific configuration
    • implements multi-tasking virtual machine to execute exrail scripts

  • Hardware Abstraction Layer (HAL) (IODevice.h, IO_*.h)

    • Provides many optional plug-in hardware device drivers for locally attached and i2c connected sensors, turnouts, lights etc.

  • WiThrottle (Withrottle.h)

    • provides support for directly connected throttles using WiThrottle protocol

  • CPU-specific layer (DCCTimer*.h)

    • provides pin and timer functions which differ between cpu types