Appendix B. Prototyping Board

Appendix B describes the features and accessories of the Prototyping Board, and explains the use of the Prototyping Board to demonstrate the RCM3000 and to build prototypes of your own circuits.

B.1 Mechanical Dimensions and Layout

Figure B-1 shows the mechanical dimensions and layout for the RCM3000 Prototyping Board.

Figure B-1. RCM3000 Prototyping Board Dimensions

Table B-1 lists the electrical, mechanical, and environmental specifications for the Prototyping Board.

Table B-1. RCM3000 Prototyping Board Specifications

Parameter	Specification
Board Size	5.25" × 6.75" × 1.00" (133 mm × 171 mm × 25 mm)
Operating Temperature	-40°C to +70°C
Humidity	5% to 95%, noncondensing
Input Voltage	8 V to 24 V DC
Maximum Current Draw (including user-added circuits)	800 mA max. for +3.3 V supply, 1 A total +3.3 V and +5 V combined
Prototyping Area	2.0" × 3.5" (50 mm × 90 mm) throughhole, 0.1" spacing, additional space for SMT components
Standoffs/Spacers	5, accept 4-40 × 3/8 screws

B.2 Power Supply

The RCM3000 requires a regulated 3.3 V ± 0.15 V DC power source to operate. Depending on the amount of current required by the application, different regulators can be used to supply this voltage.

The Prototyping Board has an onboard +5 V switching power regulator from which a +3.3 V linear regulator draws its supply. Thus both +5 V and +3.3 V are available on the Prototyping Board.

The Prototyping Board itself is protected against reverse polarity by a Shottky diode at D2 as shown in Figure B-2.

Figure B-2. Prototyping Board Power Supply

B.3 Using the Prototyping Board

The Prototyping Board is actually both a demonstration board and a prototyping board. As a demonstration board, it can be used to demonstrate the functionality of the RCM3000 right out of the box without any modifications to either board. There are no jumpers or dip switches to configure or misconfigure on the Prototyping Board so that the initial setup is very straightforward.

The Prototyping Board comes with the basic components necessary to demonstrate the operation of the RCM3000. Two LEDs (DS1 and DS2) are connected to PG6 and PG7, and two switches (S2 and S3) are connected to PG1 and PG0 to demonstrate the interface to the Rabbit 3000 microprocessor. Reset switch S1 is the hardware reset for the RCM3000.

The Prototyping Board provides the user with RCM3000 connection points brought out conveniently to labeled points at headers J2 and J4 on the Prototyping Board. Small to medium circuits can be prototyped using point-to-point wiring with 20 to 30 AWG wire between the prototyping area and the holes at locations J2 and J4. The holes are spaced at 0.1" (2.5 mm), and 40-pin headers or sockets may be installed at J2 and J4. The pinouts for locations J2 and J4, which correspond to headers J1 and J2, are shown in Figure B-3.

Figure B-3. RCM3000 Prototyping Board Pinout
(Top View)

The small holes are also provided for surface-mounted components that may be installed around the prototyping area.

There is a 2.0" × 3.5" through-hole prototyping space available on the Prototyping Board. +3.3 V, +5 V, and GND traces run along the edge of the Prototyping Board for easy access.

B.3.1 Adding Other Components

There are two sets of pads that can be used for surface mount prototyping SOIC devices. The silk screen layout separates the rows into six 16-pin devices (three on each side). However, there are pads between the silk screen layouts giving the user two 52-pin (2× 26) SOIC layouts with 50 mil pin spacing. There are six sets of pads that can be used for 3- to 6-pin SOT23 packages. There are also 60 sets of pads that can be used for SMT resistors and capacitors in an 0805 SMT package. Each component has every one of its pin pads connected to a hole in which a 30 AWG wire can be soldered (standard wire wrap wire can be soldered in for point-to-point wiring on the Prototyping Board). Because the traces are very thin, carefully determine which set of holes is connected to which surface-mount pad.

B.3.2 Measuring Current Draw

The Prototyping Board has a current-measurement feature available on header JP1. Normally, a jumper connects pins 1-2 and pins 5-6 on header JP1, which provide jumper connections for the +5 V and the +3.3 V regulated voltages respectively. You may remove a jumper and place an ammeter across the pins instead, as shown in the example in Figure B-4, to measure the current being drawn.

Figure B-4. Prototyping Board Current-Measurement Option

B.3.3 Attach Modules to Prototyping Board

Turn the RCM3000 module so that the Ethernet connector end of the module extends to the right, as shown in Figure B-5 below. Align the module headers J1 and J2 into sockets J12 and J13 (the MASTER slots) on the Prototyping Board. Press the module's pins firmly into the Prototyping Board headers.

Figure B-5. Install the RCM3000 on the Prototyping Board

NOTE

It is important that you line up the pins of the module headers exactly with the corresponding pins on the Prototyping Board. The header pins may become bent or damaged if the pin alignment is offset, and the module will not work. Permanent electrical damage to the module may also result if a misaligned module is powered up.

With the RCM3000 plugged into the MASTER slots, it has full access to the RS-232 transceiver, and can act as the "master" relative to another RabbitCore RCM3000 or RCM3100 plugged into the SLAVE slots, which acts as the "slave."

B.3.4 Other Prototyping Board Modules and Options

An optional LCD/keypad module is available that can be mounted on the Prototyping Board. Refer to Appendix C, "LCD/Keypad Module," for complete information.

A motor control option is available for development by the customer. Refer to Appendix F, "Motor Control Option," for complete information on using the Rabbit 3000's Parallel Port F in conjunction with this application.