VMIC VMIVME-1128 | VMEbus Dual-Port RAM Module | Obsolete Embedded Computing Spare Parts Risk
VMIC VMIVME-1128 | VMEbus Dual-Port RAM Module | Obsolete Embedded Computing Spare Parts Risk - Image 2
VMIC VMIVME-1128 | VMEbus Dual-Port RAM Module | Obsolete Embedded Computing Spare Parts Risk - Image 3

VMIC VMIVME-1128 | VMEbus Dual-Port RAM Module | Obsolete Embedded Computing Spare Parts Risk

  • Model: VMIVME-1128
  • Brand: VMIC (acquired by GE Fanuc, later part of Emerson and then discontinued)
  • Core Function: Dual-port static RAM (DPRAM) module for VMEbus systems—enables high-speed, low-latency data sharing between multiple VME boards or between VME and host computers
  • Lifecycle Status: Obsolete (End-of-Life) – discontinued in the early 2000s; no new production for over two decades
  • Procurement Risk: Extreme – only available on surplus/gray markets; no manufacturer support, repair, or documentation updates
  • Critical Role: Serves as a real-time communication backbone in tightly coupled multi-processor VME systems (e.g., radar processing, power plant control, test equipment); failure breaks inter-board data coherence and can halt entire applications
Category: SKU: VMIC VMIVME-1128

Description

Key Technical Specifications (For Spare Part Verification)

  • Product Model: VMIVME-1128
  • Manufacturer: VMIC (VME Microsystems International Corporation)
  • Bus Interface: VME64 (6U form factor, P1/P2 connectors), compatible with 32-bit VMEbus (A24/D32)
  • Memory Type: Static RAM (SRAM), non-volatile option not standard
  • Capacity: 128 KB (organized as 64K x 16 bits)
  • Access Time: Typically 25–55 ns (depending on speed grade)
  • Ports: Two independent, fully asynchronous ports with separate address/data/control buses
  • Interrupt Support: Onboard interrupt logic for port-to-port signaling (via VME IRQ lines)
  • Address Mapping: Configurable via DIP switches or jumpers for base address and memory window
  • Power: +5 V DC (primary), ±12 V (optional for interface buffers)
  • Form Factor: Standard 6U VME card (233.35 mm × 160 mm)
  • Compatibility: Works with Motorola 680×0, PowerPC, and Intel-based VME single-board computers (SBCs) from Force, DY4, Condor, etc.

System Role and Downtime Impact

The VMIVME-1128 was widely deployed in real-time embedded systems where deterministic inter-processor communication was critical—such as:
  • Nuclear reactor protection systems (e.g., Westinghouse OCS)
  • Military radar and sonar signal processors
  • Power grid phasor measurement units (PMUs)
  • Semiconductor test handlers
In these applications, one CPU might acquire sensor data while another performs control calculations, with the VMIVME-1128 acting as the shared “blackboard.” A failure (e.g., SRAM bit corruption, port lockup) causes data desynchronization, leading to logic errors, safety system faults, or complete application crash. Because VME systems often lack software-based redundancy for shared memory, this module represents a single point of failure with severe operational consequences.

Reliability Analysis and Common Failure Modes

Despite robust industrial design, the VMIVME-1128 is highly susceptible to age-related degradation after 20+ years:
  • SRAM cell leakage or latch-up: Causes intermittent data corruption, especially at elevated temperatures
  • Capacitor aging on power decoupling circuits: Leads to voltage droop and read/write errors
  • Oxidation of edge connectors or socket contacts: Increases impedance and causes bus timeouts
  • Latch failure in address decoder logic: Results in incorrect memory mapping or bus conflicts
  • Firmware-less design: No self-diagnostics; faults are only detectable via application-level checksums
Environmental stressors like thermal cycling, radiation (in nuclear settings), and vibration accelerate wear. Recommended preventive actions include:
  • Periodic memory integrity testing using diagnostic software (e.g., VxWorks BSP tests)
  • Cleaning and reseating the card annually
  • Monitoring VME bus error counters on the system controller
  • Maintaining multiple verified spares with burn-in testing
VMIC VMIVME-1128

VMIC VMIVME-1128

Lifecycle Status and Migration Strategy

VMIC was acquired by GE Fanuc in 2003, and the VMIVME-1128 was discontinued shortly thereafter. The product line was eventually sunsetted under Emerson’s ownership. No official replacements exist, and even datasheets are now archived or paywalled.
Short-term mitigation:
  • Source tested units from reputable defense/aerospace surplus suppliers (e.g., Rochester Electronics, if available)
  • Implement application-level CRC or redundancy over shared memory
  • Create a hardware emulator using FPGA-based VME cards (e.g., from MEN Mikro or EKF)
Long-term migration path:
  1. Replace VME chassis with modern VPX or CompactPCI Serial platforms featuring integrated DDR4 shared memory or PCIe peer-to-peer
  2. Virtualize legacy VME software on ruggedized x86 servers with VME-to-PCIe bridge cards (limited determinism)
  3. Full system rewrite using modern real-time OS (e.g., Linux PREEMPT_RT, QNX) and Ethernet-based time-triggered communication (e.g., TSN, DDS)
Given the mission-critical nature of many VMIVME-1128 deployments, organizations should conduct a formal obsolescence risk assessment and prioritize migration—especially in regulated industries where component traceability and long-term support are mandatory. Continuing to operate on untested surplus units poses unacceptable reliability and safety risks.

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