Microconnect MC-PCIE-MCS2S Internal Serial

Microconnect MC‑PCIE‑MCS2S Internal Serial Card

The Microconnect MC‑PCIE‑MCS2S is a high‑performance internal serial interface card designed for modern computer systems that require reliable RS‑232 communication. Built around the MCS9901 controller (a variant of the ASIX AX99100), this PCIe expansion module delivers two full‑featured serial ports with exceptional data integrity and low latency.

Key Technical Specifications

• Interface: PCI Express 2.0 x1 (backward compatible with PCIe 1.x)
• Serial Ports: 2 × RS‑232/RS‑422/RS‑485 capable ports
• Controller: MCS9901 (ASIX AX99100) – dual UART, FIFO buffers, DMA support
• Data Rates: Up to 4 Mbps per port (standard RS‑232/RS‑422/RS‑485 speeds)
• Voltage Levels: 3.3 V logic; supports ±12 V, +5 V, and +24 V signal ranges
• Pin Configuration: Standard DB9 connectors for each port (optional RJ45 or custom breakout)
• Operating Temperature: –40 °C to +85 °C (industrial grade)
• Power Consumption: < 1 W during active operation
• Dimensions: 2.5 in × 0.6 in (typical PCIe card size)
• Compliance: CE, FCC, RoHS compliant

Design and Architecture

The MC‑PCIE‑MCS2S integrates the MCS9901 controller directly onto a compact PCB. The dual UARTs are each equipped with 256 byte FIFO buffers to absorb burst traffic, while DMA channels offload data transfer from the CPU, ensuring minimal interrupt overhead. The board includes robust level‑shifting circuitry that allows seamless interfacing with a wide range of industrial devices, from legacy serial terminals to modern fieldbus gateways.

Installation and Compatibility

Installing the MC‑PCIE‑MCS2S is straightforward:

1. Insert the card into an available PCIe x1 slot on a compatible motherboard.
2. Connect the desired serial devices to the DB9 ports (or use breakout cables for RJ45).
3. Power on the system; the operating system should automatically detect the two UARTs and load the appropriate drivers (Linux, Windows, or embedded RTOS). The driver package includes utilities for configuring baud rate, parity, stop bits, and flow control.

The card is fully compatible with mainstream desktop, workstation, and industrial PC platforms that support PCIe 2.0 x1. It also works seamlessly in embedded systems such as single‑board computers or custom chassis where space and power budgets are tight.

Use Cases and Applications

• Industrial Automation: Connect to PLCs, SCADA systems, and motor controllers that rely on RS‑232/RS‑422 communication.
• Telecommunications: Interface with legacy modems, network switches, or fiber optic transceivers requiring serial control.
• Aerospace & Defense: Reliable data exchange with avionics equipment and ground support systems.
• Medical Equipment: Secure communication with diagnostic devices that use RS‑232 for configuration and status monitoring.
• Research & Development: Rapid prototyping of serial protocols in lab environments.

Performance Highlights

The MCS9901 controller’s DMA engine allows data throughput up to 4 Mbps per port without burdening the CPU, which is critical for high‑speed logging or real‑time control loops. The dual FIFO buffers reduce frame loss during burst transmissions, and the hardware flow control (RTS/CTS) ensures that connected devices can manage backpressure effectively.

Software Support

The driver suite includes:

• Linux kernel module with standard serial API support.
• Windows COM port drivers compatible with legacy and modern applications.
• Embedded firmware for RTOS environments (FreeRTOS, VxWorks).
• Configuration utilities that expose advanced settings such as UART mode selection (RS‑232/422/485), parity inversion, and automatic baud rate detection.

Reliability and Durability

Designed for industrial use, the MC‑PCIE‑MCS2S features:

• Robust PCB layout with controlled impedance traces for serial signals.
• High‑quality connectors rated for 10 000+ insertion cycles.
• Thermal management through a metal chassis and heat spreader, ensuring stable operation even under continuous load.

Conclusion

The Microconnect MC‑PCIE‑MCS2S Internal Serial Card delivers a compact, high‑throughput serial interface solution for demanding industrial and commercial applications. Its dual UART architecture, DMA acceleration, and versatile voltage support make it an ideal choice for engineers seeking reliable RS‑232/RS‑422/RS‑485 connectivity in modern PCIe platforms.