28029 Parallax Inc, 28029 Datasheet - Page 46

• Manufacturer Part Number: 28029
• Description: KIT PARTS SMART SENSORS W/TEXT
• Manufacturer: Parallax Inc

Specifications of 28029

• Accessory Type: Parts Kit
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: BASIC Stamp® or Javelin Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant
• Other names: 28029PAR

Page 34 · Smart Sensors and Applications
SUMMARY
The liquid crystal display (LCD) is used in a tremendous variety of products. Simple
character displays like the Parallax 2X16 serial LCD can substitute for the Debug
Terminal's display features, which is especially useful when the test site for your project
is not within reach of a serial cable and PC.
The Parallax Serial LCD has a contrast adjustment potentiometer on the back, along with
two switches you can use to select from three different baud rates and a self-test mode.
There are three pins on the back of the Parallax Serial LCD, as only three connections are
needed to operate it: Vdd, RX, and Vss.
The Parallax Serial LCD has an extensive command set, and a full list of these commands
is included in the Parallax Serial LCD Product Documentation (Appendix B). This
chapter introduced commands for turning the display on and off, clearing it, cursor
placement, backlighting control for the backlit model, and character display.
The Parallax Serial LCD depends on serial messages from the BASIC Stamp that are
programmed into it by the PBASIC
command. Many of the
command's
SEROUT
DEBUG
features can be used with the
command, including text between quotation marks
SEROUT
and formatters like
,
,
, and so on. These all have LCD results that are similar
DEC
BIN
DIG
to the Debug Terminal. The LCD's control codes are different from and more numerous
than the ones used with the Debug Terminal. Instead of trying to use
,
,
,
CR
CLS
CRSRXY
etc, use the control code values listed in the LCD's command set. It's also a good idea to
make constants for these values, such as
,
,
LcdCls CON 12
LcdClr CON 13
LcdOn CON
,
, and so on.
22
LcdOff CON 21
The Parallax Serial LCD has eight custom characters, 0 to 7. You can display any one of
them by sending its value to the LCD. For example,
makes the
SEROUT 14, 84, [3]
LCD print Custom Character 3. The commands to define custom characters range from
248 to 255. Sending
instructs the LCD to define Custom Character 0,
defines
248
249
Custom Character 1, and so on, up to
, which defines Custom Character 7. After
255
sending a Define Custom Character command, the next eight bytes are binary values, the
lower five bits of which define the pixels in a given line of pixels. A 1 makes the pixel
black, and a 0 makes it white.