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Key Technical Specifications
| Parameter | Specification |
| Bus Interface | G-64 Bus / G-96 Bus Compatible |
| Board Format | Single Eurocard (100 mm x 160 mm) |
| Memory Socket Type | Standard 28-pin DIP sockets |
| Supported Devices | Static RAM (SRAM), EPROM, EEPROM, FLASH DIP ICs |
| Addressing Mode | Configurable base address decoding via DIP switches / jumpers |
| Data Bus Width | 8-bit / 16-bit access modes (system dependent) |
| Backup Power | Onboard Lithium battery or external supply line for non-volatile RAM retention |
| Operating Temperature | 0°C to +70°C (Industrial Grade) |
| Power Consumption | Ultra-low CMOS standby power mode |
Product Introduction & Supply Chain Strategy
The Gespac GESMEM-12D is a specialized static RAM/EPROM memory expansion board engineered for legacy G-64 and G-96 bus industrial automation architectures. Widely deployed across 1980s and 1990s European industrial control systems, CNC equipment, robotics, and rail electronics, this single-Eurocard module provides flexible, battery-backed non-volatile RAM and firmware storage for Motorola 68000, 6809, and Intel-based host microprocessors.
Because Gespac hardware is now obsolete, finding functional hardware replacements is essential for maintaining production lines without costly complete control retrofits. Sourcing verified GESMEM-12D modules ensures exact pin-out compatibility with existing G-64 backplanes. Due to the age of these units, onboard backup batteries should be routinely inspected and replaced before installation to prevent RAM corruption or parameter loss during power cycles.
Installation & Configuration Guide
1.Pre-Installation Preparation:Disconnect system power and observe ESD guidelines.
Power down the G-64 rack and isolate incoming power. Attach an anti-static wrist strap. Remove the existing memory board or prepare the target card slot for installation.
2.Jumper & Switch Configuration:Configure memory bank jumpers and base address settings.
Verify the DIP switches and shorting jumpers on the GESMEM-12D match the memory layout required by your host CPU board. Set the memory base address, wait states, and device capacity jumpers (e.g., for 8Kx8, 32Kx8, or 128Kx8 SRAM/EPROM chips).
3.Socketing & Battery Check:Insert ICs and check battery voltage.
Ensure all DIP memory ICs are firmly seated with correct pin 1 orientation. Check the onboard backup battery voltage using a DMM to ensure non-volatile CMOS SRAM data retention during power-off states.
4.Physical Installation & Verification:Seat module into backplane and reapply rack power.
Align the GESMEM-12D with the guide rails and slide it firmly into the DIN 41612 connector of the G-64 backplane. Reapply power, execute system diagnostics, and verify that the host CPU correctly maps the memory address space.
GESMEM-12D
GESMEM-12D
Firmware/Software Integration & Memory Mapping
- Passive Hardware Architecture: The GESMEM-12D contains no microcontrollers or embedded firmware; it functions purely as an address-decoded memory array.
- Memory Mapping: Address decoding is managed entirely via onboard jumper arrays. Ensure target address spaces do not overlap with existing CPU system RAM, boot ROM, or I/O spaces.
- Data Retention: When using standard low-power CMOS SRAMs, the onboard lithium cell maintains data integrity when the main system power is turned off.
Frequently Asked Questions (FAQ)
Q: What bus standard does the GESMEM-12D use?
A: The operates on the G-64 standard bus (Eurocard format with a DIN 41612 connector), widely used in European industrial automation systems.
Q: Can this board accept both EPROM and static RAM (SRAM) chips?
A: Yes, the board features flexible jumper configurations that allow individual memory banks to be populated with either SRAM or EPROM devices depending on pinout and voltage settings.
Q: Why is my losing stored parameters when power is shut down?
A: Data loss in RAM during power-off indicates a depleted onboard lithium backup battery or incorrect power-retention jumpers. Replacing the backup battery typically restores parameter retention.
Q: Are these boards brand new or refurbished?
A: Due to the legacy nature of Gespac components, these units are supplied as New Surplus or fully tested Pre-Owned original components cleaned and verified for industrial service.
