Description
Core Product Summary
The Gespac GESMEM-12D is a high-reliability VMEbus-compatible DRAM memory extension board engineered for legacy industrial automation, embedded computing systems, and real-time processing architectures. Built on the single Eurocard (3U) form factor, it provides system memory expansion for Gespac G-64/G-96 and 16/32-bit VMEbus single-board computers (SBCs) and processing nodes.
Designed for demanding industrial control environments, the GESMEM-12D features dynamic RAM storage with high-speed access times, zero-wait-state bus interface logic, and parity check capabilities. Its low-power design and standard DIN connector layout allow seamless slot integration into standard 3U VMEbus or G-96 subracks, offering stable data buffering and program execution space in real-time embedded control racks.
Key Technical Specifications
| Specification Parameter | Verified Value |
| Manufacturer | Gespac |
| Product Model | GESMEM-12D |
| Product Type | DRAM Memory Expansion Module |
| Bus Compatibility | VMEbus / G-96 Bus Standard |
| Board Form Factor | Single Eurocard (3U) |
| Data Bus Width | 8-bit / 16-bit Configurable Data Access |
| Addressing Mode | 24-bit VMEbus Addressing Space |
| Connector Type | DIN 41612 Standard Indirect Connector |
| Operating Voltage | +5 VDC (Supplied via Backplane) |
| Error Protection | Parity Checking Logic with Error Detection Signal |
| Operating Temperature | 0°C to +70°C Standard Industrial Range |
Detailed Product Overview
The Gespac GESMEM-12D was developed to expand volatile system memory across 16-bit and 32-bit embedded processing platforms utilizing Eurocard subrack standards. In industrial processing and legacy automation setups, memory board selection directly impacts bus throughput and execution speed. The GESMEM-12D utilizes high-density dynamic RAM chips paired with dedicated refresh logic to ensure continuous access without interrupting the host CPU’s instruction cycle.
With its 24-bit addressing range and flexible bus decoding, the module can be mapped anywhere within the VMEbus system address space via hardware jumper configurations. This enables multi-card configurations or non-overlapping shared memory access across multi-processor subracks.
The single Eurocard form factor and DIN 41612 backplane interface offer high immunity to vibration, mechanical shock, and industrial electrical noise. The board’s parity logic actively monitors data transfers, asserting a bus error or interrupt signal upon detecting memory bit anomalies to preserve system stability in critical real-time operations.
System Compatibility & Integration Requirements
| Item / Dependency | Verified Compatibility or Requirement | Practical Note |
| System Bus | VMEbus / G-64 / G-96 Backplanes | Connects via standard 3U backplane slots. |
| Processor Compatibility | Motorola 68000 / 68020 / 68030 series SBCs | Supports standard 8-bit and 16-bit cycle transfers. |
| Backplane Power | Standard 5 VDC VMEbus Power Rail | Power is drawn entirely through the DIN backplane connector. |
| Mechanical Subrack | Standard 19-inch / 3U Eurocard Subrack | Requires one 3U slot width (4 HP). |
| Address Configuration | On-board Jumper / DIP Switch Settings | Configures base address offset within the system address map. |
GESMEM-12D
GESMEM-12D
Dimensions, Mounting & Connection Notes
- Form Factor: Standard 3U Single Eurocard.
- Dimensions: 100 mm × 160 mm (3.937 in × 6.299 in).
- Slot Width: Single-slot 4 HP width.
- Backplane Connection: DIN 41612 96-pin connector.
- Mounting Method: Slide-in card guide mounting within standard 3U subracks with front panel retaining screws.
- Operating Temperature Range: 0°C to +70°C.
FAQ
What is the Gespac GESMEM-12D?
The Gespac GESMEM-12D is a 3U Single Eurocard DRAM memory expansion module designed for VMEbus and G-96 industrial computer systems.
Which bus architectures are compatible with the GESMEM-12D?
It is compatible with standard 3U VMEbus systems as well as Gespac G-64 and G-96 bus subracks.
How is the module powered?
The module receives its nominal +5 VDC power directly through the DIN 41612 backplane connector.
Does the GESMEM-12D include error detection?
Yes, the board includes on-board parity checking logic to detect data transmission anomalies across the bus.
How is the memory address set on the board?
The base address mapping within the system memory space is set using on-board jumper fields prior to installation.
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