Detailed Product Description of XYCOM XVME-20 I. Product Overview

The XVME-200 is a 3U single-height VMEbus universal TTL digital I/O module launched by XYCOM (now part of Acromag/Xembedded). It provides 32 TTL-level input/output channels, dual 24-bit timers, hardware handshake and VME interrupt capabilities for VME industrial control systems. It emphasizes high cost-effectiveness and flexible configuration, and is widely used in industrial automation, equipment monitoring and timing control scenarios. Core positioning

Standard 3U VMEbus (IEEE 1014 2.0/3.0) from device module;

Same series: XVME-201 (48 channels), XVME-290 (6U with the same function);

Adaptation: Semiconductor devices, industrial robots, power/chemical control, military/aerospace embedded systems.

II. Core Functional Characteristics

1. VMEbus standard interface (fully compatible)

Bus protocol: IEEE 1014 VMEbus 2.0/3.0;

Address space: A16 (64KB), base address configurable via jumper;

Data width: D16/D08 (EO), supports 8/16-bit data transmission;

Interrupt capability: Supports IRQ1–IRQ7, programmable interrupt vector and priority;

Backplane connection: Only requires P1 connector, no P2 needed.

2. 32-channel TTL I/O (software configurable direction)

Channel configuration: 32 TTL levels (5V), divided into 4 independent 8-bit ports (Port A–D);

Direction control: Each port is independently set as input or output (configured by control register);

Electrical specifications:

Input high level ≥ 2.0V, low level ≤ 0.8V;

Output pull-in / pull-out current 24mA, directly drives TTL load;

Input buffer / output latch, anti-interference design;

Port characteristics: fully buffered, with handshake signals (ACK/STB), suitable for printers, PLCs, etc. peripherals.

3. Dual 24-bit timers / counters (MC68230 PI/T)

Chip: Integrates 2 Motorola MC68230 PI/T (parallel interface / timer);

Timers: 2 independent 24-bit timers, maximum count 16,777,215;

Working modes:

Single-shot / cyclic timing;

Pulse width modulation (PWM);

Event counting / frequency measurement;

Delay trigger / pulse generation;

Interrupt trigger: Timer overflow can trigger VME interrupt, achieving precise timing control.

4. Hardware handshake and interrupt response

Hardware handshake: Each port is equipped with ACK (response) / STB (selection) signal, suitable for high-speed peripheral data interaction;

Interrupt trigger sources:

Input channel level change;

Timer count overflow;

Handshake signal status change;

Programmable interrupt: Supports IRQ1–IRQ7, interrupt vector can be software-configured, priority can be adjusted.

5. Industrial-grade high reliability design

Operating temperature: 0℃～+70℃;

Storage temperature: -40℃～+85℃;

Anti-vibration: 1g (10–100Hz); anti-shock: 15g;

EMC compliance: CE/FCC Class A, gold-plated gold fingers, shielding design;

Power consumption: +5V@0.8A (typical 4W), low heat generation;

Connectors: Front panel 2×50-pin SCSI-II, pin compatible with OPTO 22 isolation module, convenient for strong current isolation.

6. Panel status indication

POWER: Power normal always on;

RUN: Module running / self-check passed;

INT: Flashes when interrupt triggered;

Port A–D ACT: Flashes when port is read/write.

III. Hardware Specification Overview

Bus parameters Table

Project Specifications

Bus standard VMEbus IEEE 1014 (2.0/3.0)

Address space A16 (64KB)

Data width D16/D08 (EO)

Interrupts IRQ1–IRQ7, programmable vector

Backplane interface P1 (no P2 required)

I/O channel parameters Table

Project Specifications

Number of channels 32 channels, TTL (5V), 4×8-bit ports

Direction configuration Each port is set as input/output by software

Input level High ≥ 2.0V, Low ≤ 0.8V

Output drive Pull/Load current 24mA

Handshake signal ACK/STB (per port)

Connector 2×50-pin SCSI-II (OPTO 22 compatible)

Timer parameters Table

Project Specifications

Chip 2×Motorola MC68230 PI/T

Number of Timers 2 independent 24-bit

Maximum Count Value 16,777,215

Resolution 1μs (typical)

Operating Modes Timing, Counting, PWM, Interrupt Trigger

Electrical / Environmental Parameters Table

Project Specifications

Power Supply +5V DC ±5%, 0.8A (4W)

Operating Temperature 0℃ to +70℃

Storage Temperature -40℃ to +85℃

Vibration Resistance 1g (10–100Hz)

Impact Resistance 15g

Size 3U (100×160mm), single slot

Weight Approximately 0.3kg

V. Comparison with Similar Series Models Table

Model Number of Channels Form Timer Key Differences

XVME-200 32 TTL 3U 2×24 bits General standard type, high cost-performance ratio

XVME-201 48 TTL 3U 2×24 bits High-density I/O, 16 more channels

XVME-290 32 TTL 6U 2×24 bits 6U chassis compatibility, P2 backplane output

V. Typical Application Scenarios

Industrial automation control: Line switch quantity control, motor start/stop, electromagnetic valve / valve control, alarm light driving;

Equipment status monitoring: Limit switch, proximity switch, photoelectric switch signal acquisition, panel button / indicator light control;

Precise timing control: Timed triggering, delay switch, PWM speed control, pulse generation / counting;

Data acquisition and event recording: Encoder pulse counting, frequency measurement, equipment operation event capture;

Upgrade of old VME systems: Direct replacement of modules of the same series, no need to modify hardware / rewrite programs, extend equipment lifespan.

VI. Installation and Programming Key Points Installation steps

Confirm that the P1 slot of the VME chassis is normal and the +5V power supply is stable;

Jumper configuration: base address, interrupt vector, handshake mode (optional);

Insert the module into the 3U slot, fix the panel screws;

Connect the front panel 2×50-pin SCSI-II to the on-site I/O or OPTO 22 isolation module;

Power-on self-test: POWER is constantly on, RUN is lit, INT does not flash, indicating normal operation.

Programming flow (simplified)

Address mapping: configure A16 base address, map module registers to system memory;

Port direction configuration: write control register, set Port A-D as input or output;

Output control: write output port register, control output level (high/low);

Input reading: read input port register, obtain the status of external devices;

Timer configuration: set timer initial value, working mode, interrupt enable;

Interrupt service program: write interrupt handling logic to respond to input changes or timing events.

VII. Core advantages

High cost-effectiveness: 32-channel TTL I/O + dual timers, comprehensive functions, economical price;

Flexible configuration: port direction can be set by software, base address/interrupt can be programmed, suitable for multiple scenarios;

Industrial-grade reliability: wide temperature range, shock resistance, gold-plated gold fingers, suitable for harsh conditions;

Strong compatibility: standard VMEbus, OPTO 22 compatible connectors, easy integration;

Long lifecycle: production discontinued but spare parts are sufficient, suitable for maintenance and upgrade of old VME systems.

VIII. Notes

The module is discontinued: procurement mainly relies on second-hand / refurbished spare parts, need to confirm the test report;

Battery backup: no onboard battery, data is not saved when power fails, critical data requires external storage;

Heat dissipation requirements: working temperature 0℃～+70℃, ensure good ventilation of the chassis;

Electrostatic protection: during installation / maintenance, need to prevent static electricity, avoid static damage to chips.