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 Jackrabbit 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 Jackrabbit Prototyping Board.

Figure B-1. Jackrabbit Prototyping Board

B.2 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 Jackrabbit 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.

Once you have looked at the basic sample programs described in the Jackrabbit Getting Started manual, solder the headers included in the bag of spare parts onto the Prototyping Board. Solder a 10-pin header to the Top Side at location J1. Solder the additional headers shown in Figure B-2 onto the Bottom Side.

Figure B-2. Where to Solder Additional Headers

B.2.1 Demonstration Board

A relay, a thermistor, four additional LEDs, and a serial cable are included in a bag of parts to further allow exploration of the Jackrabbit`s operation.

The SPDT relay handles 120 V at 5 A with a 12 V activating coil. The layout to accept this relay is included on the Bottom Side of the Prototyping Board. Note that the relay coil connections need to be wired to one of the sinking high-power outputs (HV0-HV2) of the Jackrabbit. Install the relay on the bottom side of the Prototyping Board, as shown in Figure B-3.

Figure B-3. Installation of Relay on Prototyping Board

NOTE	COIL(+) must be connected to a 12 V power supply when using the relay. This is the nominal voltage supplied as +RAW when the transformer supplied with the Development Kit is used, and in this case you may connect COIL(+) to +RAW. If you use another power supply, connect COIL(+) to +12 V if +RAW is different.
NOTE	If you do use the transformer supplied with the Development Kit for COIL(+), be aware that its voltage may be as high as 16 V at low current draws. This needs to be taken into consideration if you plan to use a 12 V relay in critical applications.

The thermistor has a nominal room-temperature resistance of about 10 kW, which drops to about 6 kW at 40°C. Once you solder the thermistor onto the RT1 pads (see Figure B-4) on the Prototyping Board, the A/D readings on AD0 will change with temperature.

Figure B-4. Thermistor and
Potentiometer Locations

If the 10 kW potentiometer is removed, the A/D change with temperature will be larger.

The LEDs can be mounted in positions DS5-DS8, shown in Figure B-5, to display the complete status for Parallel Port A.

Figure B-5. LED Location

The serial cable included in the parts bag can be used to connect the Jackrabbit's RS-232 outputs from header J1 on the Prototyping Board to an available DE9 PC serial port.

Unlike the CMOS-level signals on header J3, the programming port on the Jackrabbit board, the signals on header J1 on the Prototyping Board are full RS-232 level signals without needing the CMOS to RS-232 converter that is present in the programming cable. The RS-232 level signals are processed via the MAX232 transceiver chip, U4, on the Jackrabbit board to Serial Ports B and C of the Rabbit 2000. The CMOS-level signals on the programming port are connected to Serial Port A.

B.2.2 Prototyping Board

To maximize the availability of Jackrabbit resources, the demonstration hardware (LEDs, switches, potentiometer, buzzer) on the Prototyping Board may be disconnected. This is done by cutting the traces seen between and within the silk-screen outline of headers JP1 and JP2 on the Prototyping Board. Figure B-6 shows the 16 places where cuts should be made. An exacto knife or high-speed precision grinder tool like a Dremel® tool would work nicely to cut the traces. Alternatively, if safety is a major concern, a small standard screwdriver may be carefully and forcefully used to wipe through the PCB traces.

Figure B-6. Where to Cut Traces to Permanently Disable
Demonstration Hardware on Prototyping Board

Jumpers across the appropriate pins on headers JP1 and JP2 can be used to reconnect specific demonstration hardware later if needed. Each pin is labeled on the PCB to facilitate placing the jumpers. The jumper positions are summarized in Table B-1.

Table B-1. Prototyping Board Jumper Settings

Header JP1		Header JP2 (continued)
Pins	Description	Pins	Description
1-2	Buzzer	5-6	PA2 to LED DS3
3-5	K to +5 V	7-8	PA3 to LED DS4
5-6	K to +RAW	9-10	PA4 to LED DS5
7-8	Potentiometer or Thermistor	11-12	PA5 to LED DS6
9-10	Interrupt Enable	13-14	PA6 to LED DS7
Header JP2		15-16	PA7 to LED DS8
Pins	Description	17-18	PB2 to switch S1
1-2	PA0 to LED DS1	19-20	PB3 to switch S2
3-4	PA1 to LED DS2	21-22	PB4 to switch S3

Once the LEDs, resistors, and switches are disconnected as described above, the user has a Jackrabbit board with connection points conveniently brought out to labeled points at headers J3 and J7 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 J3 and J7. Note that the pinouts at locations J3 and J7 on the Bottom Side of the Prototyping Board (shown in Figure B-7) are a mirror image of the Jackrabbit board pinouts.

Figure B-7. Jackrabbit I/O Pinout on Prototyping Board (Bottom Side)

A user-supplied DE9 connector can be added as shown in Figure B-2. The signals are brought out to location J5 on the Top Side of the Prototyping Board.

There are six independent surface-mount 14- to 16-pin SOIC pads and fourteen 3- to 5-pin SOT23 pads. Each component has every one of its pin pads connected to a hole in the prototyping area. The layout is such that there is another SOIC or SOT23 pad directly on the other side of the PCB from the SOIC or SOT23 pads. However, each layout location is routed to its unique set of connection holes. Because the traces are very thin, carefully determine which set of holes is connected to which surface-mount pad. There are several standard 0805 passive-component surface-mount pads. These pads are not routed to wiring holes so wire must be soldered directly to the component. In addition, there is a large generic array of wide traces connected to large holes. This is provided as an additional area for surface-mount passive components. There is a moderate amount of 0.1" arrayed through-hole prototyping area (about 137 holes) for mounting through-hole components.

Thus, many circuits requiring special circuitry external to the Jackrabbit can be prototyped and tested with the Prototyping Board. If additional prototyping space is needed, install 40-pin headers at locations J3 and J7 on the Bottom Side of the Prototyping Board to connect to sockets that you would install at J3 and J7 on the Top Side of a second Prototyping Board.