User`s manual

40 RabbitCore 2000

B.3.1 Adding Other Components

There is room on the Prototyping Board for a user-supplied RS-232 transceiver chip at

location U2 and a 10-pin header for serial interfacing to external devices at location J6. A

Maxim MAX232 transceiver is recommended. When adding the MAX232 transceiver at

position U2, you must also add 100 nF charge storage capacitors at positions C3–C6 as

shown in Figure B-6.

Figure B-6. Location for User-Supplied RS-232 Transceiver

and Charge Storage Capacitors

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 (2x26)

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 resis-

tors 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.

RN1

JP1

DS3

DS2

DS1

C4 C5

RESET

PB3

PB2

PA1

PA0

DS3

DS2

PWR

GND

RXB

TXB

TXCRXC

RS-232

MAX232

100 nF

storage

capacitors