User's Manual
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| RabbitCore RCM3100 User's Manual |
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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 RCM3100 and to build prototypes of your own circuits.
B.1 Introduction
The Prototyping Board included in the Development Kit makes it easy to connect an RCM3100 module to a power supply and a PC workstation for development. It also provides some basic I/O peripherals (switches and LEDs), as well as a prototyping area for more advanced hardware development.
For the most basic level of evaluation and development, the Prototyping Board can be used without modification.
As you progress to more sophisticated experimentation and hardware development, modifications and additions can be made to the board without modifying or damaging the RCM3100 module itself.
The Prototyping Board is shown below in Figure B-1, with its main features identified.
B.1.1 Prototyping Board Features
- Power Connection—A power-supply jack and a 3-pin header are 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 V+ input. The cable of the AC adapter provided with the North American version of the Development Kit ends in a plug that connects to the power-supply jack. The header plug leading to bare leads provided for overseas customers can be connected to the 3-pin header in either orientation.
- Users providing their own power supply should ensure that it delivers 8–24 V DC at 8 W. The voltage regulators will get warm while in use.
- Regulated Power Supply—The raw DC voltage provided at the POWER IN jack is routed to a 5 V switching voltage regulator, then to a separate 3.3 V linear regulator. The regulators provide stable power to the RCM3100 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 RCM3100'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 connected to the PG0 and PG1 pins of the master RCM3100 module and may be read as inputs by sample applications.
- Two LEDs are connected to the PG6 and PG7 pins of the master 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. +3.3 V, +5 V, and Ground buses run around the 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.
- Master Module Connectors—A set of connectors is pre-wired to permit installation of the first RCM3000, RCM3100, or RCM3200 module that serves as the primary or "master module."
- Slave Module Connectors—A second set of connectors is pre-wired to permit installation of a second, slave RCM3000, RCM3100, or RCM3200 module. This capability is reserved for future use, although the schematics in this manual contain all of the details an experienced developer will need to implement a master-slave system.
- Module Extension Headers—The complete pin sets of both the MASTER and SLAVE RabbitCore modules are duplicated at these two sets of headers. Developers can solder wires directly into the appropriate holes, or, for more flexible development, 26-pin header strips can be soldered into place. See Figure B-4 for the header pinouts.
- RS-232—Two 3-wire or one 5-wire RS-232 serial port are available on the Prototyping Board. Refer to the Prototyping Board schematic (090-0137) for additional details.
- A 10-pin 0.1-inch spacing header strip is installed at J5 to permit connection of a ribbon cable leading to a standard DE-9 serial connector.
- Current Measurement Option—Jumpers across pins 1–2 and 5–6 on header JP1 can be removed and replaced with an ammeter across the pins to measure the current drawn from the +5 V or the +3.3 V supplies, respectively.
- Motor Encoder—A motor/encoder header is provided at header J6 for future use.
- LCD/Keypad Module—Rabbit Semiconductor's LCD/keypad module may be plugged in directly to headers J7, J8, and J10.
B.2 Mechanical Dimensions and Layout
Figure B-2 shows the mechanical dimensions and layout for the Prototyping Board.
NOTE All measurements are in inches followed by millimeters enclosed in parentheses. All dimensions have a manufacturing tolerance of ±0.01" (0.25 mm). Table B-1 lists the electrical, mechanical, and environmental specifications for the Prototyping Board.
B.3 Power Supply
The RCM3100 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 AC adapter supplied with the RCM3100 Development Kit provides 12 V at up to 1 A as the input to the voltage regulator on the Prototyping Board. 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-3.
B.4 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 RCM3100 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 RCM3100. 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 RCM3100.
The Prototyping Board provides the user with RCM3100 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-4.
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.4.1 Adding Other Components
There are pads that can be used for surface-mount prototyping involving SOIC devices. There is provision for seven 16-pin devices (six on one side, one on the other side). There are 10 sets of pads that can be used for 3- to 6-pin SOT23 packages. There are also 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.4.2 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-5, to measure the current being drawn.
B.4.3 Other Prototyping Board Modules and Options
With the RCM3100 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, RCM3100, or RCM3200 plugged into the SLAVE slots, which acts as the "slave."
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.
The RCM3100 has a 2-channel quadrature decoder and a 10-bit free-running PWM counter with four pulse-width registers. These features allow the RCM3100 to be used in a motor control application, although Rabbit Semiconductor does not offer the drivers or a compatible stepper motor control board at this time.
The Prototyping Board has a header at J6 to which a customer-developed motor encoder may be connected. Figure B-6 shows the motor encoder pinout at header J6.
Refer to Appendix E, "Motor Control Features," for complete information on using the Rabbit 3000's Parallel Port F in conjunction with this application.
B.5 Use of Rabbit 3000 Parallel Ports
Table B-2 lists the Rabbit 3000 parallel ports and their use for the RCM30/31/32XX Prototyping Board.
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