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Emerald-MM-Opto 4-Port Opto Serial Module
Quad Opto-Isolated RS-232/422/485 Port PC/104 Module with DIO
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Description |
Emerald-MM-Opto provides an integrated, rugged, and reliable solution for PC/104-expandable embedded systems requiring serial communications in demanding applications. It offers 2 or 4 optically isolated serial ports with RS-232, RS-422, and RS-485 protocols, as well as 24 digital I/O lines, all on a single board.
Optical isolation of 1000V DC or AC protects your embedded system from ground differentials or noise spikes that would damage non-isolated boards. Each port is isolated from the other ports as well as the system. Extended temperature capability (-40 to +85ºC) enables the board to operate in vehicles such as trains and buses without concern for temperature swings. These features enable Emerald-MM-Opto to provide reliable serial communications in harsh environments such as trains and buses.
In addition to ruggedness, Emerald-MM-Opto offers flexibility and advanced features. Each serial port is independently configurable for protocol and IRQ settings. Eight different I/O address combinations are built in. The 16C2850 UART chips with 128-byte FIFOs support high-speed data rates at up to 460kbps without overloading the system processor. Auto-flow control enables easy RS-485 operation by automatically enabling and disabling the transmitter during data transmission, to prevent bus conflicts or excessive software overhead.
Emerald-MM-Opto also offers multiple termination methods on the serial ports to support varying interface requirements. In RS-422 or RS-485 networks, termination resistors are normally installed at the endpoints of the cables to minimize reflections on the lines. The board provides jumper-selectable termination and pull-up/pull-down resistors for this purpose. The sensible jumper positioning and layout help simplify board configuration and minimize confusion.
The 24 digital I/O lines are based on an 82C55 chip and feature programmable direction in 4- and 8-bit groups. All I/O lines contain user-configurable 10K Ohm pull-up resistors for convenience. This 2-in-1 combination of serial ports and digital I/O can help lower the size and cost of your embedded system by eliminating one additional board from your PC/104 stack.
Diamond Systems offers appropriate mating cables for your convenience. Cable no. C-DB9M-1 provides a DB-9 male connector with standard PC serial port pinout. Each serial port requires one cable. Cable no. C-26-18 is a 26-conductor ribbon cable for the digital I/O lines.
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System Block Diagram |
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Configuration |
The following I/O addresses are selected with jumpers or 0-ohm resistors. All addresses are in hex.
| A |
B |
C |
Port 1 |
Port 2 |
Port 3 |
Port 4 |
Interrupt status |
| In |
In |
In |
3F8-3FF |
2F8-2FF |
3E8-3EF |
2E8-2EF |
220 |
| Out |
In |
In |
3E8-3EF |
2E8-2EF |
3A8-3AF |
2A8-2AF |
220 |
| In |
Out |
In |
380-387 |
388-38F |
288-28F |
230-23F |
224 |
| Out |
Out |
In |
240-247 |
248-24F |
260-267 |
268-26F |
224 |
| In |
In |
Out |
100-107 |
108-10F |
110-117 |
118-11F |
240 |
| Out |
In |
Out |
120-127 |
128-12F |
130-137 |
138-13F |
244 |
| In |
Out |
Out |
140-147 |
148-14F |
150-157 |
158-15F |
248 |
| Out |
Out |
Out |
160-167 |
168-16F |
170-177 |
178-17F |
24C |
The interrupt status register indicates the pending interrupt status of all 4 serial ports. It is a read-only register. Only bits 3-0 are used. Bits 7-4 read back as 0 always.
| Bit |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
| Function |
0 |
0 |
0 |
0 |
IRQD |
IRQC |
IRQB |
IRQA |
IRQD-A = interrupt status for ports 4-1, respectively. 1 = interrupt pending, 0 = no interrupt pending.
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I/O Headers |
Each serial port has its own 10-pin (2x5) pin header with the following pinouts. These pinouts are consistent with the pinout of the SP334 transceiver for each mode.
(NC = no connection)
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RS-232 Configuration |
RS-422 Configuration |
RS-485 Configuration |
| 1 |
NC |
RXD+ |
TXD+/RXD+ |
| 2 |
NC |
CTS- |
NC |
| 3 |
RXD |
RXD- |
TXD-/RXD- |
| 4 |
RTS |
RTS+ |
NC |
| 5 |
TXD |
TXD+ |
TXD+/RXD+ |
| 6 |
CTS |
CTS+ |
NC |
| 7 |
NC |
TXD- |
TXD-\RXD- |
| 8 |
NC |
RTS- |
NC |
| 9 |
ISO GND |
ISO GND |
ISO GND |
| 10 |
NC |
NC |
NC |
In RS-485 mode, only one pair of signal wires is used, plus ground reference. Either pins 1 and 3 or pins 5 and 7 may be used. These signal pairs are duplicated on the connector due to the jumpering of the RX and TX lines on the configuration jumper block.
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Digital I/O |
The digital I/O is provided on a 26-pin (2x13) pin header with the following pinout.
| C7 |
1 |
2 |
C6 |
| C5 |
3 |
4 |
C4 |
| C3 |
5 |
6 |
C2 |
| C1 |
7 |
8 |
C0 |
| B7 |
9 |
10 |
B6 |
| B5 |
11 |
12 |
B4 |
| B3 |
13 |
14 |
B2 |
| B1 |
15 |
16 |
B0 |
| A7 |
17 |
18 |
A6 |
| A5 |
19 |
20 |
A4 |
| A3 |
21 |
22 |
A2 |
| A1 |
23 |
24 |
A0 |
| +5V |
25 |
26 |
GND |
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Specifications |
| Serial Ports |
2 or 4, RS-232/422/485 |
| Data Rates |
RS-232, 230.4kbps max
RS-422/485: 460.8kbps max |
| Signals |
RS-232: RXD, TXD, RTS, CTS
RS-422/485: RXD, TXD |
| Addresses |
8 preconfigured standard I/O address options; custom addresses available |
| Interrupts |
IRQ levels 2, 3, 4, 5, 6, 7, 10, 12, 15;
Interrupt sharing supported |
| Isolation |
1000V AC or DC, port to port or port to system |
| Termination |
150Ω with 1KΩ pull-up/pull-down |
| UART |
16C2850 with 128-byte FIFO and auto-flow control |
| Digital I/O |
24 programmable direction using 82C55 |
| DIO termination |
10KΩ pull-up |
| Connectors |
Individual 10-pin connector for each serial port; 26-pin connector for digital I/O |
| Bus |
PC/104 16-bit bus (8-bit data) |
| Power |
+5VDC @ 300mA typical, all outputs open |
| Operating Temperature |
-40ºC to +85ºC |
| Dimensions |
3.550"W x 3.775"H |
| RoHS |
Compliant |
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Get an online quote |
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Emerald-MM-Opto 4-Port Opto Serial Module |
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| 4 Opto-Isolated RS-232/422/485 + 24 Digital I/O |
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Cables and accessories |
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| Dual 26-pin connectors, 18 inches |
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| 10-pin to DB9M, 18 inches |
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