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Products   >   I/O Expansion Modules   >   Communications Modules   >   Emerald-MM-8PLUS 8-Port Serial Module

Emerald-MM-8PLUS 8-Port Serial Module

High Performance PC/104-Plus 8 Port RS232/422/485 Serial I/O Module

Emerald-MM-8PLUS  8-Port Serial Module: I/O Expansion Modules, Rugged, wide-temperature PC/104, PC/104-<i>Plus</i>, PCIe/104 / OneBank, PCIe Minicard, and FeaturePak modules featuring standard and optoisolated RS-232/422/485 serial interfaces, Ethernet, CAN bus, and digital I/O functions., PC/104-<i>Plus</i>
Block Diagram
Operating Systems Compatibility
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Emerald-MM-8Plus is a high performance multi-protocol serial communications board offering eight ports on a single PC/104-Plus module. Supporting baud rates up to 921.6K bps in RS-232 mode or 1.8432Mbps in RS422 or RS485 mode, each port can be individually selected for RS-232, RS-422, RS-485 or TTL level operation. Both local-echo and non-local-echo modes are supported for RS-485. Protocol selection is achieved via a jumper block for each of the eight ports. Line termination for RS-422/485 modes is also jumper-selectable.

Configuration of the Emerald-MM-8Plus is simple, using the built-in plug and play technology. For manual configuration, the base address for the board may be set in software, defining a 4K block of configuration space used to access the on-board registers. A single 32-bit read shows the detailed interrupt status for each of the eight ports. The PCI “slot” is defined through a jumper block. As with all Diamond Systems products, jumpers are paralleled with locations for zero ohm resistors to create a rugged, shock-and- vibration-resistant implementation.

Emerald-MM-8Plus is based on the Exar 17D158 octal UART IC. This device contains 8 4 identical sets of 16C55registers, one for each port, and is compatible with the standard PC serial port. Each port contains 64-byte transmit and receive FIFOs to support the high-speed data rates.

Emerald-MM-8Plus also offers 8 convenient digital I/O lines. The direction of each line is independently programmable. Finally, Emerald-MM-8Plus also offers a 16-bit programmable counter / timer with a configurable clock source.

Two I/O headers are provided, with four serial ports and four digital I/O lines on each header. The board operates on +5V only, eliminating the need for a +12V supply that is often required for serial port operation.

Block Diagram

Emerald-MM-8PLUS Block Diagram

Operating Systems Compatibility

The Emerald-MM-8Plus is compatible with Windows 98/NT/2000/XP and Linux. If using Exar's default Vendor and Device ID, you can use Exar's module driver for Linux kernels 2.4.x and Linux kernels 2.6.1-2.6.7. Linux kernels 2.6.8 and newer have support in the kernel for the XR17x15x PCI UARTs. See the "8250_pci.c" in the kernel. If using your own Vendor and Device ID, you can use the module driver available from Exar after you modify the Vendor and Device ID accordingly in the module driver.


Serial Ports
Number of serial ports 8
Protocols RS-232, RS-422, RS-485 (local and no echo)
Protocol Configuration Jumpers
Software Configuration Plug and Play
Maximum baud rate 1.8432Mbps
Communications parameters 5, 6, 7, or 8 data bits; Even, odd, or no parity
Short circuit protection Continuous, all outputs
RS-232 mode
Input Impedance 3KΩ min
Input voltage swing ±30V maximum
Output voltage swing ±5V min, ±7V typical
RS-422/RS-485 modes:
Differential input threshold -0.2V min, +0.2V max
Input impedance 12KΩ minimum
Input current +1.0mA max (Vin = 12V)
-0.8mA max (Vin = -7V)
Differential output voltage 2.0V min (RL=50Ω)
High/low states differentia
output voltage symmetry
0.2V max
Digital I/O
Number of I/O lines 8 individually programmable
Input voltage Logic 0: -0.3V min, 0.8V max
Logic 1: 2.0V min, 5.3V max
Output voltage 0: 6mA max
1: -4mA max
I/O header 2 40-position (2x20) .025" square pin header on .1" centers;
Headers mate with standard ribbon cable (IDC) connectors
Dimensions 3.55" x 3.775"
Power supply +5VDC ±10%
Current consumption 160mA typical, all outputs unloaded
Operating temperature -40°C to +85°C standard, all versions
Weight 3.1oz (87.9g)
RoHS Compliant


8 serial ports with up to 1.8432Mbps data rates
Exar 17D158 octal UARTS with 64-byte FIFOs
Configurable for RS-232/RS-422/RS-485 protocols or simple TTL level operation
Plug and Play configuration
Supports interrupt sharing
8 programmable digital I/O lines
Dual 40-pin I/O headers, 4 ports per header
+5V only operation
-40°C to +85°C operation
PC/104-Plus form factor
Customers who use this product also use:
4-port DB9 Serial Cable

This product can be customized and ruggedized. Click here for more information.
See Emerald-MM-8PLUS 8-Port Serial Module Technical Resources
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Emerald-MM-8Plus Datasheet
(.pdf, 221.7 kb)
Emerald-MM-8PLUS User Manual
(.pdf, 525.1 kb)

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Emerald-MM-8PLUS 8-Port Serial Module
available models:
8 RS-232/422/485 Serial Ports PC/104-Plus Module
Transition cable for Condor C2626 GPS module
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Cables and accessories
available models:
Quad DB9 male to 40-pin header 18" cable, Serial ports 1-4 (uses 2)
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VDC 2006 Platinum Vendor Award