20-101-0709 Rabbit Semiconductor, 20-101-0709 Datasheet - Page 27

• Manufacturer Part Number: 20-101-0709
• Description: INTERFACE GRAPHIC DISPLAY OP6700
• Manufacturer: Rabbit Semiconductor

Specifications of 20-101-0709

• Module/board Type: Single Board Computer Module
• For Use With/related Products: OP6700
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 20-101-709; 20-101-709

3.2.1 RS-232
The Intellicom’s RS-232 serial channel is connected to an RS-232 transceiver, U11. U11
provides the voltage output, slew rate, and input voltage immunity required to meet the
RS-232 serial communication protocol. Basically, the chip translates the Rabbit 2000’s 0
V to +Vcc signals to RS-232 signal levels. Note that the polarity is reversed in an RS-232
circuit so that +5 V is output as approximately -10 V and 0 V is output as approximately
+10 V. U11 also provides the proper line loading for reliable communication.
The maximum baud rate is 115,200 bps. RS-232 can be used effectively at this baud rate
for distances up to 15 m.
3.2.2 RS-485
The Intellicom has one RS-485 serial channel, which is connected to the Rabbit 2000
serial port B through U10, an RS-485 transceiver. The chip’s slew rate limiters provide for
a maximum baud rate of 250,000 bps, which allows for a network of up to 1200 m (or
4000 ft). The half-duplex communication uses the Rabbit 2000’s PC0 pin to control the
data enable on the communication line.
The RS-485 signals are available on pins 3 and 4 of header J7, and on J5, the RJ-12 jack.
The Intellicom can be used in an RS-485 multidrop network. Connect the 485+ to 485+
and 485– to 485– using single twisted-pair wires (nonstranded, tinned) as shown in
Figure 9.
Alternatively, the RS-485 multidrop network may be hooked up using cables with RJ-12
plugs. Note that the RJ-12 jack has +RAW_485 and GND, which means that only one
Intellicom needs to be connected to an external power source via an AC adapter. When
doing so, ensure that the AC adapter has sufficient capacity for the network — each Intel-
licom unit nominally draws 100 mA at 24 VDC.
User’s Manual
NOTE: The RS-485 port is available only in the factory default configuration. The RS-485
CAUTION: If you plan to connect a power supply to more than one
in an RS-485 network using the RJ-12 jacks, rework the RS-485 cables so they do not
connect +RAW_RS485 through the RJ-12 jack to the boards in the network.
port will not be available when you select the configuration option for both 3-wire
RS-232 ports or one 5-wire RS-232 port.
Intellicom unit
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