Real-Time Clock & Interrupt Module (RCIM IV)

The Real-Time Clock & Interrupt Module (RCIM) is a multifunction PCIe timing and synchronization card designed for deterministic, time-critical applications running on Concurrent Real-Time iHawk systems. It provides a centralized timing reference and flexible interrupt management, enabling precise coordination of processes across single or multiple systems.

Built for simulation, data acquisition, and industrial control environments, the RCIM allows engineers to maintain accurate timing relationships between applications, CPUs, and distributed systems. By combining a high-resolution synchronized clock with programmable real-time clocks and configurable interrupt lines, the RCIM ensures predictable system behavior even under complex workloads.

Deterministic Timing Across Systems

At the core of the RCIM is a 64-bit synchronized system clock that provides a common time base across all connected CPUs and systems. This clock operates as a free-running counter with nanosecond-level resolution, allowing applications to reference a consistent, high-precision timeline.

In multi-system configurations, one RCIM can be designated as the master, automatically synchronizing all connected systems at startup. This ensures that all applications—regardless of where they are running operate against the same time reference, simplifying event correlation, logging, and system validation.

Programmable Real-Time Clocks

The RCIM includes eight independent, programmable real-time clocks, each capable of generating interrupts based on user-defined timing intervals. These clocks function as decrementing counters and can be configured for:

• One-shot execution
• Periodic operation with automatic reload
• Custom timing intervals down to microsecond resolution

This makes the RCIM ideal for driving cyclic processes, scheduling deterministic workloads, and maintaining consistent execution frequencies across applications.

Flexible External Interrupt Handling

To support integration with external hardware and custom signal environments, the RCIM provides twelve configurable external interrupt lines, each individually selectable as input or output.

These interrupt lines can be configured for:

• Edge-triggered operation (rising or falling edge)
• Level-sensitive operation (high or low level)

Applications can dynamically control interrupt behavior, including enabling or disabling lines, selecting trigger modes, and adjusting polarity. This flexibility allows engineers to tailor the system to a wide range of real-world signal conditions without hardware changes.

Distributed Interrupt Architecture

The RCIM enables low-latency interrupt distribution across multiple systems, allowing events detected on one CPU to be propagated to others in real time. This capability is critical for applications that require coordinated responses across distributed environments, such as hardware-in-the-loop (HIL) simulation and large-scale test systems.

Interrupts can be generated by:

• External input signals
• Programmable real-time clocks
• Software-driven events

Once generated, these interrupts can be routed locally or distributed across connected RCIM modules, ensuring consistent system-wide behavior.

Scalable Multi-System Synchronization

Using a simple serial synchronization cable, multiple RCIM-equipped systems can be daisy-chained together to form a unified, time-synchronized network. This architecture allows engineers to scale from a single system to a multi-rack or distributed deployment while maintaining deterministic timing and coordinated execution.

For applications requiring absolute time alignment, an optional GPS synchronization module is available. This allows systems to align their internal clocks with GPS time, enabling synchronization even between physically separated systems.

Seamless Software Integration

The RCIM is fully supported by RedHawk Linux, allowing developers to access timing and interrupt features directly within their applications. Integration with Concurrent’s NightStar tools further enhances visibility and control, enabling:

• Reading and logging synchronized system time
• Routing and managing interrupts across systems
• Synchronizing application execution using real-time clocks
• Analyzing system behavior with a unified time reference

This tight integration ensures that developers can fully leverage the RCIM’s capabilities without introducing additional complexity into their workflows.

Built for Real-Time Applications

The RCIM is purpose-built for environments where timing accuracy, determinism, and system coordination are critical. Typical applications include:

• Hardware-in-the-Loop (HIL) and simulation systems
• Real-time data acquisition and signal processing
• Industrial automation and control systems
• Multi-system test and validation environments

By providing a reliable timing backbone and flexible interrupt infrastructure, the RCIM helps engineers reduce system complexity, improve synchronization accuracy, and ensure consistent real-time performance.