Densan DVE-68K/42 MC68040 Processor Board

The Densan DVE-68K/42 is a VMEbus-compatible CPU board built around the Motorola MC68040 processor, delivering 66 MHz core performance in a double-height, single-slot form factor. This industrial-grade board integrates 16 MB of DRAM, 8 MB of fixed flash memory, dual ROM sockets, and a Compact Flash Type 1 interface, making it suitable for embedded systems requiring reliable compute and storage in compact installations. The board features dual 24-bit timers, two DMA controllers, a watchdog timer, and battery-backed RTC with 512 KB SRAM. Network connectivity is provided via 10BASE-T Ethernet; four-channel serial I/O via ST16C2550 controller supports legacy industrial communications. VMEbus master/slave operation across A32/A24/A16 address spaces and D32/D16/D08 data widths enables flexible system integration.

## Technical Specifications

**Processor & Memory**
• CPU: Motorola MC68040 @ 66 MHz core, 33 MHz bus clock
• Main Memory: 16 MB DRAM
• L1 Cache: 4 KB instruction, 4 KB data
• Fixed Flash: 8 MB (2× 28F320J5)
• ROM: 2× 40-pin sockets, 1 MB maximum each
• Compact Flash: Type 1 socket, True IDE Mode, 3.3V

**Peripherals & I/O**
• Serial: 4-channel, ST16C2550 controller, 9-pin D-Sub connectors
• Ethernet: 10BASE-T, RJ-45
• Timers: 2-channel, 24-bit resolution
• DMA: 2× controllers
• RTC/SRAM: M48T512 (512 KB battery-backed)
• Watchdog: 1× timer

**VMEbus Interface**
• Protocol: IEEE-1014 compliant
• Master/Slave: A32/A24/A16 address, D32/D16/D08 data
• System Controller functionality supported

**Physical & Environmental**
• Form Factor: Double Height, Single Slot (233.55 mm × 160 mm × 20 mm)
• Operating: 0°C to 60°C, 25–95% RH non-condensing
• Storage: −20°C to 70°C
• Cooling: Forced air required
• Power Input: +5V ±5%

**Indicators & Controls**
• LEDs: RUN, FAIL, GPO, GP1, LINK, ACT
• Switches: Front-panel reset, abort; 8-bit DIP configuration

## Key Features

• Cache coherency via bus snooping
• Burst-mode transfers on cache misses
• Selectable boot source via jumper configuration
• System and interrupt management via VMEbus controller

## Typical Applications

Industrial automation, real-time embedded control, legacy VMEbus system upgrades, and networked instrumentation platforms requiring deterministic compute performance and reliable persistent storage.

## Compatibility & Integration

Full VMEbus compliance enables direct integration into existing IEEE-1014 backplanes. The MC68040 architecture and standard peripheral controllers support established RTOS and firmware ecosystems developed for 680×0 platforms.