28138 Parallax Inc, 28138 Datasheet - Page 7

• Manufacturer Part Number: 28138
• Description: BOARD DEV PROFESSIONAL
• Manufacturer: Parallax Inc
• Series: BASIC Stamp®r
• Type: MCUr

Specifications of 28138

• Contents: Development Board
• Processor To Be Evaluated: SX28AC/DP
• Interface Type: RS-232
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: BASIC Stamp®, Javelin Stamp, and SX28AC/DP
• For Use With: 900-00014 - SERVO CONTROLLER PICO GWS130-28029 - KIT PARTS SMART SENSORS27957 - MANUAL USER FOR JAVELIN STAMP28138 - BOARD DEV PROFESSIONAL805-00006 - CABLE USB A TO MINI B27937 - MEMORY STICK DATALOGGER658-1021-5 - PROGRAMMER TEACLIPPER/STAMP30010 - BASIC STAMP LOGIC ANALYZER27220 - BOOK STAMPWORKS27330 - PROGRAMMER STACHE BASIC STAMP27218 - MANUAL BASIC STAMP VER 2.0
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Servo Headers (X4)
Headers X4 may be used to connect standard hobby servos to the PDB. Devices with the same pin
configuration (Signal / Vdd / Vss) may also be connected to these headers. Compatible devices include
the Parallax serial LCD module and Ping))) ultrasonic rangefinder.
10 k Potentiometer (X5 and X6)
Two 10 k potentiometers are provided via X5 and X6.
A 220  series
resistor is placed inline with the wiper connection to prevent an I/O pin from
being connected directly to Vdd or Vss.
Audio Amplifier (X7)
The onboard audio amplifier includes a filter circuit that is ideal for commands like SOUND (BS1 and
SX/B), FREQOUT (BS2-family and SX/B), and DTMFOUT (BS2-family).
A jumper allows the use of an
external 8  speaker when additional volume is required.
L293D Push-Pull Driver (X8)
The L293D push-pull driver allows the experimenter to
control high-current devices like relays, solenoids
lamps and motors to the PDB.
Its push-pull
configuration (which means it can sink or source
current on its output pins) with active-high enable
inputs makes it ideal for creating h-bridge motor driver
circuits, or for driving unipolar and bipolar stepper
motors. Note that the output-high voltage must be
supplied to the V+ terminal.
When the enable inputs are high the outputs will
follow the inputs, otherwise the outputs will be in a Hi-
Z state.
See the L293D documentation (available
separately)
for
additional
details
on
use
and
configuration.
Pushbuttons and DIP Switches (X9 and
X10)
Eight normally-open pushbuttons and eight DIP switches are made available via connectors X9 and X10.
The buttons and the switches are wired in an active-low configuration, with an I/O pin protection resistor
as shown in the illustration below.
Copyright © Parallax, Inc.
Professional Development Board (#28138)
v2.0 9/3/2008 Page 7 of 10