The Microchip/Datum bc350VXI is a B-Size (6U × 160 mm) Time and Frequency Processor module for VXIbus systems. It acquires precise time from GPS satellites or IRIG B time code signals and outputs synchronized frequency references, time-of-day data, and event-stamped records. The module combines a disciplined 10 MHz TCXO with a 100 nanosecond clock and battery-backed timekeeping to maintain accuracy across power loss events and demanding synchronization requirements in telecommunications, critical infrastructure, and metrology applications.
Technical Specifications
Physical and Interface
• Form Factor: B-Size module (6U × 160 mm)
• Bus Compatibility: VXIbus (selectable via DIP switch); VMEbus compatibility available
• Register Interface: 32 D16 registers via A16:D16 VMEbus; VXIbus operation at any of 256 Logical Addresses (A15 and A14 must be high)
Time and Frequency Generation
• Internal Clock: 100 nanosecond resolution
• Disciplined Oscillator: 10 MHz TCXO
• Battery Backup: +/−10 PPM clock for time retention during power loss
• Synchronization Modes: Six operational modes selectable by reference source
• Flywheel Operation: Maintains last known reference rate if synchronization source fails
Time Acquisition
• Primary Sources: GPS satellites; IRIG B, 2137, or XR3 time code inputs
• Time Output: On-demand time (days through 0.1 microseconds) with zero latency; front panel LED display (hours, minutes, seconds)
• Event Logging: Hardware registers capture time on positive or negative input edge with 0.1 microsecond resolution
Output Capabilities
• Frequency Outputs: Programmable TTL (1 MHz, 5 MHz, or 10 MHz), synchronized to selected reference
• Time Code Generation: IRIG B or IRIG H (modulated and DC level shift formats simultaneously)
• Pulse Per Second: 1 PPS TTL output synchronized to time of day
• Periodic Output: Programmable pulse rates or bus interrupts
• Time Strobe: Programmable single-event strobe or interrupt from hours to milliseconds resolution, including per-second mode
Digital Interface
• Event Capture: External input edge detection with optional bus interrupt generation
– Key Features
• Zero-latency time-on-demand queries
• Dual time code output formats (IRIG B and IRIG H) simultaneously
• Selectable TTL frequency outputs maintain phase lock to GPS or time code reference
• Event timestamping via dedicated hardware registers
• Programmable alarm and periodic interrupt generation
• Battery-backed operation ensures time continuity during power failures
– Typical Applications
• Telecommunications synchronization and network timing
• Precision measurement and metrology systems
• Critical infrastructure timing and event logging
• Instrumentation requiring synchronized multi-module timing in VXI chassis
– Compatibility & Integration
The bc350VXI integrates into standard VXIbus (B-Size) and VMEbus (A16:D16) backplanes. DIP switch configuration selects bus mode. The module’s 32-register block accommodates flexible logical address assignment in VXIbus environments and fixed A16:D16 addressing in VMEbus systems.
