Diamond Systems EMERALD-MM-8E/EL PC/104-Express 4- and 8-Port Multiprotocol Serial Modules for Embedded Systems

Serial links still carry much of the control and telemetry traffic in vehicles and rugged equipment, and long cable runs between subsystems invite ground loops and noise. The Diamond Systems EMERALD-MM-8E/EL series answers that on the PCIe side of the stack: PCI/104-Express serial I/O modules that add four or eight multiprotocol ports through a PCIe x1 link on the PCIe/104 OneBank connector, with optional opto-isolation for the installations that need it.

Every port in the EMERALD-MM-8E/EL series runs from a 16550-compatible octal UART with 256-byte transmit and receive FIFOs and automatic RS-485 transmit control, and each has its own SP330 transceiver. RS-232, RS-422 or RS-485 is chosen per port in software, together with programmable 120 ohm termination, and rates reach 1 Mbps in RS-232 mode and 10 Mbps in RS-422/485 mode. There are no configuration jumpers: an on-board microcontroller holds the settings in flash and loads them at power-up. The same microcontroller drives eight auxiliary lines, each usable as digital input or output, with seven also available as 12-bit analog inputs on 0 to 2.048 V or 0 to 3.3 V ranges. Every port has ±15 kV ESD protection and its own latching connector.

The range comes in four builds. The EMM-8EL-XT has eight ports, each independently isolated to 2500 V RMS, for vehicle and long cable installations where ground potential differences are expected. The EMM-4EL-XT keeps that isolation with four ports. The EMM-8E-XT offers eight non-isolated ports for devices that share the host ground, and the EMM-4E-XT is the four-port non-isolated version. Cable kits with individual DB9 male cables and a ribbon cable for the auxiliary I/O are available for the four-port and eight-port boards.

All EMERALD-MM-8E/EL modules run from 5 V DC at around 160 mA typical with outputs unloaded, with staggered turn-on of the isolated power circuits to limit inrush current. They operate from -40 to 85 °C, and Diamond Systems specifies them as MIL-STD-202G compatible for shock and vibration, with a quoted MTBF of 579,352 hours at 20 °C. A graphical control panel, a console application and drivers for Windows and Linux handle configuration on the bench or inside application software. On a PCIe/104 host such as a SATURN SBC or a GEMINI board, the series adds rugged serial expansion in one stack position.