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> Garnet-MM PC/104 Digital I/O Module
End of Life Product, product only available as Minimum Order Quantity Product
For replacement product see GPIO-MM
Garnet-MM PC/104 Digital I/O Module
48-Line High Current Digital I/O PC/104 Module
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Description |
Garnet-MM is a PC/104-format digital I/O board with 48 lines of I/O. It contains two 82C55 ICs, each having 3 8-bit I/O ports. Each 82C55 has its own 50-pin I/O header for external connections. Direction on all ports is selected by programming control registers built in to the 82C55 chips.
All I/O lines are buffered with transceivers, whose directions are controlled by logic which responds to the direction control values written to the 82C55s. Each line is capable of sourcing 35mA in a logic low state or sinking 6mA in a logic high state. The board is constructed entirely with CMOS logic to reduce power consumption and requires only +5V for operation.
Garnet-MM's I/O headers are organized to allow direct interfacing to OPTO-22's isolated I/O racks, including the G4 series, the PB16-H, -J, -K, -L, PB8H, and the PB24HQ. These racks and I/O modules allow up to 3000 VRMS isolation between the computer and the user's signals. All control signals, power, and ground on the Garnet-MM I/O header match the corresponding signals on these I/O racks, so a single 50-pin ribbon cable, such as Diamond Systems' C50-3, is all that is needed to make the connection.
The board provides access to interrupt levels 2-7 on the PC bus for real-time background applications. Interrupts can be generated in two ways. In Mode 0 operation, a rising edge on one of four interrupt lines causes the board to generate an interrupt request on the bus. In Mode 1 operation, the 82C55 generates interrupts in response to handshake signals between Garnet-MM and external circuitry.
Software drivers are included with Garnet-MM to allow controlling the board from Microsoft C, QuickC, GW-Basic, and QuickBasic languages. The software driver supports all of the board's features, including interrupt operation. Example programs demonstrate the use of the function calls and provide a starting point for program development.
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High-Current Capability for Solid State Relays |
Garnet-MM was specifically designed for applications that use mechanical or solid state relays, such as the OPTO22 G4 series. These devices typically require more drive current than many digital I/O cards can supply. For example, an OPTO22 output module requires 12mA of drive current, whereas a typical 82C55-based digital I/O card can only supply 2.5mA. However, all output lines on Garnet-MM have high-current buffers capable of driving up to 64mA each when low and 15mA each when high. This is enough for solid state relays and many mechanical relays as well. These output buffers change direction automatically in response to the direction control bytes written to the board. In addition, power and ground for the rack are provided straight from the board's I/O header, along with the data lines needed to read from and write to the relays.
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Free Software |
Garnet-MM comes with free driver software compatible with C and Basic languages. Example programs are included to get you started quickly. Some examples of the supported board operations are:
- Digital input, bit, byte, and word
- Digital output, bit, byte, and word
- Interrupt-driven digital I/O with external trigger
- I/O Header Pinout
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I/O Header Pinout |
| A7 |
1 |
2 |
Digital Ground |
| A6 |
3 |
4 |
Digital Ground |
| A5 |
5 |
6 |
Digital Ground |
| A4 |
7 |
8 |
Digital Ground |
| A3 |
9 |
10 |
Digital Ground |
| A2 |
11 |
12 |
Digital Ground |
| A1 |
13 |
14 |
Digital Ground |
| A0 |
15 |
16 |
Digital Ground |
| C7 |
17 |
18 |
Digital Ground |
| C6 |
19 |
20 |
Digital Ground |
| C5 |
21 |
22 |
Digital Ground |
| C4 |
23 |
24 |
Digital Ground |
| C3 |
25 |
26 |
Digital Ground |
| C2 |
27 |
28 |
Digital Ground |
| C1 |
29 |
30 |
Digital Ground |
| C0 |
31 |
32 |
Digital Ground |
| B7 |
33 |
34 |
Digital Ground |
| B6 |
35 |
36 |
Digital Ground |
| B5 |
37 |
38 |
Digital Ground |
| B4 |
39 |
40 |
Digital Ground |
| B3 |
41 |
42 |
Digital Ground |
| B2 |
43 |
44 |
Digital Ground |
| B1 |
45 |
46 |
Digital Ground |
| B0 |
47 |
48 |
Digital Ground |
| +5V |
49 |
50 |
Digital Ground |
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Specifications |
| Digital I/O |
| Chip |
82C55 (qty. 2) |
| Number of I/O lines |
48 |
| Direction |
Programmable in groups of 4 or 8 |
| Input voltage |
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| Low: |
-0.0V min, 0.8V max |
| High: |
2.0V min, Vcc max |
| Output voltage |
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| Low: |
0.0V min, 0.55V max |
| High: |
2.0V min, Vcc -0.3V max |
| Output current |
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| Logic 0: |
64mA max per line |
| Logic 1: |
15mA max per line |
| Output drivers |
74F245/74F243 |
| General |
| Power supply |
+5V ±10% @ 160mA typical |
| Temperature |
0° to +70°C |
| PC/104 Bus |
8 bits |
| Weight |
-24: 2.7 oz/76g
-48: 3.0 oz/85g |
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Get an online quote |
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Garnet-MM PC/104 Digital I/O Module |
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| Garnet-MM 48-line High-current Digital I/O
Minimum Order Quantity of 50 |
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Cables and accessories |
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| 50-conductor .1" pitch 18" ribbon cable Data Acquisition (GMM-48 uses 2) |
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