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RabbitCore RCM3750
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B.2.1 Features
Power Connection
—A 3-pin header is provided for connection to the power supply.
Note that the 3-pin header is symmetrical, with both outer pins connected to ground and
the center pin connected to the raw DCIN input. The cable of the AC adapter provided
with the North American version of the Ethernet Connection Kit ends in a plug that
connects to the power-supply header, and can be connected to the 3-pin header in either
orientation.
Users providing their own power supply should ensure that it delivers at least 200 mA
at 7.5–15 V DC. The voltage regulator will get warm while in use.
Linear Power Supply
—The raw DC voltage provided at the POWER IN jack is
routed to a 5 V linear voltage regulator. The regulator provides stable power to the
RCM3720 module and the Prototyping Board.
Power LED
—The power LED lights whenever power is connected to the Prototyping
Board.
Reset Switch
—A momentary-contact, normally open switch is connected directly to the
RCM3720’s /RESET_IN pin. Pressing the switch forces a hardware reset of the system.
I/O Switches and LEDs
—Two momentary-contact, normally open switches are con-
nected to the PF4 and PB7 pins of the RCM3720 module and may be read as inputs by
sample applications.
Two LEDs are connected to the PF6 and PF7 pins of the RCM3720 module, and may
be driven as output indicators by sample applications.
Prototyping Area
—A generous prototyping area has been provided for the installation
of through-hole components. +5 V and ground buses run along the bottom edge of this
area. Several areas for surface-mount devices are also available. (Note that there are
SMT device pads on both top and bottom of the Prototyping Board.) Each SMT pad is
connected to a hole designed to accept a 30 AWG solid wire or wire-wrap wire.
Module Extension Headers
—The complete pin set of the RCM3720 module is dupli-
cated at header J2. Developers can solder wires directly into the appropriate holes, or,
for more flexible development, a 2 × 20 header strip with a 0.1" pitch can be soldered
RS-232
—An optional through-hole RS-232 chip may be installed at U1 or a surface-
mount RS-232 chip may be installed at U3. (Five 0.1 F capacitors also need to be
added for the RS-232 circuit to work.) When stuffed, the RS-232 chip brings out Serial
Ports C and D to the header J3 area on the RCM3720 Prototyping Board. An optional
2 × 5 header strip with a 0.1" pitch can be installed at J3 to allow you to connect a rib-
bon cable that leads to a standard DB-9 serial connector.
Two 3-wire serial ports or one 5-wire RS-232 serial port are then available at header J3.
Backup Battery
—A 2032 lithium-ion battery rated at 3.0 V, 220 mAh, provides
battery backup for the RCM3720 SRAM and real-time clock.