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Glossary

Definitions of common terms used on the site

  • Access Point -- Generic term for the wireless interface device that bridges a desktop computer and the implanted COSMIIC System. The Wireless Link functions as an Access Point, connecting to the computer via USB.

  • Accelerometer -- A sensor measuring acceleration in three axes. An accelerometer is integrated into each module.

  • Bandpass Filter -- A signal processing filter that extracts a specific frequency band from a recorded signal. Used in the BP2 module for EMG signal processing.

  • Between Channel Timing -- The configurable delay (default 1 ms) between stimulation pulses delivered on different channels within the same SYNC period.

  • Biocompatibility -- The assessment of a material's safety and compatibility with biological tissue. Required for all implanted and patient-contacting components.

  • Biphasic Waveform -- A two-phase stimulation pulse consisting of a positive phase followed by a negative phase, designed to ensure charge balance and safe tissue stimulation.

  • Bootloader -- A special state of the microprocessor that enables a download of a new application program. The state is protected by safety interlocks. A bootloader program runs in a protected section of the microprocessor memory so that it cannot be modified or erased.

  • BP2 (Biopotential Recording Module) -- A remote implanted module for recording myoelectric signals from 2 channels. The BP2 processes EMG signals used for neuroprosthetic control.

  • CAN (Controller Area Network) -- A low-level industry-standard network protocol used in the COSMIIC System.

  • CANopen -- A high-layer set of specifications and protocols built on top of CAN that enables modular devices to communicate using a producer-consumer messaging model and a standardized Object Dictionary.

  • COB-ID -- The communication object identifier used to address PDO and SDO messages in CANopen.

  • Control Tower (CT) -- A formerly used external device that served as a gateway between a computer and the implanted system. Now obsolete. By convention, it was assigned node number 8.

  • COSMIIC -- An open-source ecosystem created through a NIH SPARC-funded project providing access to the Networked Neuroprosthetic (NNP) System for neuromodulation research and development.

  • Development Board / Dev Board -- A benchtop version of the implantable modules, used with a frame board for testing and development without surgical implantation.

  • Device Firmware Update (DFU) Mode -- A boot mode on the Wireless Link that allows firmware uploads without a JTAG hardware interface.

  • EEPROM -- Non-volatile memory used for persistent storage of module parameters and configuration that must survive a power cycle.

  • EMG (Electromyography) -- The recording and analysis of myoelectric signals generated by muscle contractions.

  • Epimysial Electrode -- An electrode designed for placement on the surface of a muscle (the epimysium). Uses a platinum-iridium disk contact sewn onto the epimysium. Associated with green connectors.

  • Failsafe Mechanism -- A three-level safety system in the COSMIIC System consisting of hardware charge limits, software parameter limits, and magnetic switches to prevent unsafe operation.

  • Firmware -- The embedded software that runs on each COSMIIC System module, controlling its behavior and communication.

  • Flash Memory -- Non-volatile memory used to store firmware and configuration data on each module.

  • Frame Board -- A support structure for development (benchtop) modules that provides power input, network connections, and output monitoring points.

  • Heartbeat Message -- A periodic message from each remote module to the Power Module, indicating that the remote module's communication is functioning.

  • IDE (Investigational Device Exemption) -- The FDA regulatory pathway under which the COSMIIC System is studied as an investigational medical device.

  • Index -- A 16-bit address used to locate an entry in the Object Dictionary (e.g., 0x1006 is the SYNC period index).

  • Inductive Link / Wireless Charging Coil -- The contactless power transfer mechanism used to recharge the Power Module's batteries transcutaneously.

  • Inter-Phase Interval (IPI) -- The time delay between the positive and negative phases of a biphasic stimulation waveform, configurable from 5 to 100 µs.

  • Intramuscular Electrode -- An electrode designed for insertion into a muscle belly. Uses a 2 mm contact surface with a barbed anchor to maintain position. Associated with red connectors.

  • JTAG -- A hardware interface standard used for debugging and flashing firmware onto microcontrollers.

  • Log / Logging -- A data storage mechanism in the Power Module for recording system events and parameter values over time.

  • LQI (Link Quality Indication) -- A radio metric indicating the quality of the wireless link between the Wireless Link and the Power Module.

  • Magnetic Switch -- An emergency shutdown mechanism integrated into the Power Module that is activated by a strong static magnetic field, stopping all stimulation immediately.

  • MATLAB -- The programming environment used for developing custom applications with the NNP-API.

  • MedRadio -- A medical-grade radio frequency protocol operating at 433 MHz used for wireless communication between the Wireless Link and the implanted Power Module.

  • MES (Myoelectric Signal) -- The electrical signal generated by muscle contraction, recorded by the BP2 module for use as a control input.

  • Monopolar Stimulation -- A stimulation configuration in which a single electrode serves as the active contact and the device case serves as the return electrode.

  • Network Cable -- A four-conductor cable that connects COSMIIC modules to each other, carrying both power and CAN communication signals.

  • Network Management (NMT) -- A CANopen protocol for sending commands to modules, changing their operational states, and managing overall network behavior.

  • Network Port -- A connection point on a module for attaching network cables.

  • Neuroprosthetics -- Implanted or external devices that restore lost sensory or motor function through electrical stimulation.

  • NNP (Networked Neuroprosthetic) System -- An implantable neuromodulation system originally invented at Case Western Reserve University, now open source as the COSMIIC System

  • NNP-API -- A MATLAB-based API providing high-level and low-level commands for controlling the COSMIIC System. Consists of the NNPCORE and NNPHELPERS classes.

  • NNPCORE -- The low-level communication layer of the NNP-API that manages the serial port connection, Access Point radio, and SDO/NMT protocols directly.

  • NNPHELPERS -- The high-level layer of the NNP-API that extends NNPCORE with convenient commands for common operations.

  • Node / Node Number -- The value assigned to a module when it is first configured that allows it to be uniquely referenced from the Control Editor software and embedded scripts. All permanent devices have a node number. Node numbers typically exist between 1 and 20 inclusively. By convention, the Power Module is assigned node number 7 and the Control Tower is assigned node number 8.

  • OD (Object Dictionary) -- A standardized map of all accessible data and parameters across all network modules, addressed by a 16-bit index and an 8-bit sub-index.

  • PDO (Process Data Object) -- A CANopen broadcast mechanism for continuous or event-driven data transfer. Configured as either a Transmit PDO (TPDO) or Receive PDO (RPDO).

  • PG4 (4-Channel Pulse Generator) -- A remote implanted module for delivering electrical stimulation to up to 4 independent monopolar electrodes. Typically located in the extremities. By convention, PG4 modules are assigned node numbers 1–6.

  • PM (Power Module) -- The primary implanted module. Provides power from rechargeable Li-ion batteries and contains the MedRadio wireless link for transcutaneous communication. By convention, assigned node number 7.

  • Port Plug -- A protective plug placed in unused module ports during manufacturing. Removed at surgery when a network cable or electrode is connected.

  • Producer-Consumer Model -- A network communication paradigm in which modules publish data to the network without concern for which devices consume it. Used by CANopen PDOs.

  • Pulse Amplitude (PA) -- The amplitude of the stimulation current delivered to an electrode, ranging from 0 to 20 mA. Stored internally as PA × 10.

  • Pulse Width (PW) -- The duration of a stimulation pulse in microseconds, ranging from 1 to 255 µs.

  • Remote Module (RM) -- Any module connected to the COSMIIC System network other than the Power Module. Typically assigned node numbers 1–6 (PG4s) and 9–14 (BP2s).

  • RPDO (Receive PDO) -- A Process Data Object configured to receive and store data from the network.

  • RSSI (Received Signal Strength Indication) -- A measurement of radio signal power, expressed in dBm, used to assess wireless link quality.

  • RTOS (Real-Time Operating System) -- The operating system managing the multiple concurrent processing tasks running on the Power Module.

  • .nnpscript -- An assembly-like scripting language and file format that runs directly on the Power Module, enabling autonomous system operation without a continuous external computer connection.

  • Script Pointer (SP) -- The destination slot number used when loading a compiled script onto the Power Module. Slots are numbered 1–25.

  • SDO (Service Data Object) -- A CANopen request-response protocol for reading or writing individual Object Dictionary entries. More flexible but less efficient than PDOs.

  • Smart Charger -- An external device that combines the Wireless Link and a charging coil into a single unit for simultaneously communicating with and charging the Power Module.

  • Stack Usage -- A diagnostic metric reporting the memory utilization percentage for each of the 9 system tasks running on the Power Module.

  • Sub-Index / Subindex -- An 8-bit address used to access a specific field within a multi-field Object Dictionary entry.

  • SYNC (Synchronization Message) -- A cyclically transmitted CAN message that provides a reference timebase for all network operations. The SYNC message drives the scheduler that triggers stimulation pulses.

  • SYNC Period -- The time between successive SYNC messages, which determines the stimulation frequency. A minimum of 23 ms per channel is recommended.

  • Touch-Proof Connector -- A recessed electrode connection design that prevents accidental contact with the conductive contacts.

  • tPDO (Transmit PDO) -- A Process Data Object configured to stream data out from a device to the network.

  • UART -- A serial communication hardware protocol used for various internal interfaces within NNP System modules.

  • USB CDC (Communication Device Class) -- A USB protocol standard that creates a virtual serial port, used by the Wireless Link to communicate with a host computer.

  • VNET (Network Supply Voltage) -- The voltage supplied to remote modules via the network cable, ranging from 4.7 V to 9.6 V.

  • Waiting Mode -- An idle operational state in which a module responds to NMT and SDO messages but does not generate PDO messages or deliver stimulation.

  • Wake Interval -- The period at which the Power Module checks for incoming radio messages during Wake-on-Radio (WOR) mode, configurable from 14 to 255 ms (default 20 ms).

  • Wireless Link (WL) -- The external radio interface device (Access Point) that bridges to the implanted COSMIIC System through wireless communication with the Power Module.

  • WOR (Wake-on-Radio) -- A low-power mode in which the Power Module periodically awakens to check for incoming radio messages, reducing power consumption at the cost of increased communication latency.