28029 Parallax Inc, 28029 Datasheet - Page 323

• 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

Appendix B: Parallax Serial LCD Documentation · Page 311
the model 27976 and 27977 LCDs. The commands in the range Dec 128 to 207 move the
cursor to the 20 different positions on each of the four lines of the model 27979 LCD.
Controlling the Display
You also have control over the various display modes of the Serial LCD. The display-off
command (Dec 21) turns off the display so that all of the characters disappear. The
characters aren’t erased from the display, though, and you can even keep writing new
characters to the display when it is turned off. A trick to make a lot of text show up all at
once, even at a slow baud rate, is to turn off the display and then send all of your text.
Then, when you turn the display on again, all of the text appears instantly.
The display-on commands (DEC 22 to 25) turn the display back on and also control
whether you want to display the cursor and/or make the cursor character blink. The
cursor is the short bar that shows up below the character at the current cursor position.
The blink option makes that character blink on and off repeatedly. You can turn the
cursor and blink options on or off, in any combination, as listed in the command set table.
You can change the cursor and blink mode even if the display is already on; you don’t
need to turn it off and then back on again.
With models 27977 and 27979, you can also control the backlight of the display. The
backlight lights up the display so that it is easier to see in the dark. There are commands
to turn the backlight on (Dec 17) and off (Dec 18).
Custom Characters
The Serial LCD has the capability to store up to eight user-defined custom characters.
The custom characters are stored in RAM and so they need to be redefined if you turn off
the power. You can display the custom characters by sending the commands Dec 0 to 7,
as shown in the command set table. The custom character will display at the current
cursor position.
The custom characters are five pixels wide by eight pixels high. Each of the characters is
stored as a series of eight data bytes where the low five bits of each byte represent a row
of pixels in the character. The high three bits of each byte are ignored. A bit value of
one turns that pixel on (i.e. makes it black). The bottom row of pixels is often left blank
(all zeros) to make it easier to see the cursor.