Diamond Systems Emerald-MM-DIO 4-Port RS-232 and 48 Digital I/O PC/104 Module

The Emerald-MM-DIO is a PC/104 module that combines four RS-232 serial ports with 48 digital I/O lines on a single board for embedded systems. It delivers serial communication via 16C554 UARTs supporting up to 115.2 Kbps (460.8 Kbps with optional crystal), plus individually programmable digital I/O with edge detection on 24 lines. The module fits the tight footprint constraints of PC/104 applications while providing industrial-temperature operation and full interrupt sharing across multiple ports.

## Technical Specifications

**Serial Ports**
• 4× RS-232 interfaces with 16C554 UARTs (16-byte FIFOs)
• Data rates to 115.2 Kbps standard; 460.8 Kbps available with optional crystal
• Full 8-signal set plus ground per port
• Dual 20-pin (2×10) I/O headers at 0.1″ centers
• Jumper-selectable from 8 I/O address combinations and 11 interrupt levels
• Interrupt sharing fully supported with dedicated status register

**Digital I/O**
• 48 lines organized into six 8-bit ports
• Individual bit-level programmability for input or output
• Inverting logic: logic 0 tri-states and pulls high via 10 kΩ resistor (input mode); logic 1 drives low
• Output current: 0.3 mA (high state), 8 mA (low state)
• Edge detection on 24 lines with selectable high/low edge triggering and interrupt generation
• Two 2×25-pin I/O headers

**Physical & Electrical**
• Dimensions: 3.55″ × 3.775″
• Power: +5 VDC ±10%, 5V-only operation
• Typical current draw: 80 mA (all outputs unloaded)
• Operating temperature: −40°C to +85°C (extended versions available)
• Humidity: 5% to 95% non-condensing

## Key Features

• PC/104 form factor with 8-bit and 16-bit ISA bus headers
• Bit-level input/output control eliminates need for external logic
• Edge-triggered interrupts support event-driven application designs
• Full interrupt sharing allows stacking multiple modules on single IRQ
• Industrial temperature range for harsh environments

## Typical Applications

Embedded data logging, industrial control interfaces, sensor array multiplexing, legacy serial device bridging, distributed I/O expansion in confined spaces.

## Compatibility & Integration

Supports virtually all embedded operating systems via industry-standard PC/104 ISA interface. Universal Driver software provided for edge detection configuration and interrupt management.