27976 Parallax Inc, 27976 Datasheet - Page 5

• Manufacturer Part Number: 27976
• Description: MODULE SRL LCD 2X16 NON-BACKLIT
• Manufacturer: Parallax Inc

Specifications of 27976

• Display Mode: Transflective
• Interface: Serial
• Display Type: STN - Super-Twisted Nematic
• Number Of Digits/alpha: 32
• Outline L X W X H: 80.00mm x 36.00mm x 21.00mm
• Viewing Area: 61.00mm L x 15.70mm W
• Backlight: Without Backlight
• Display Format: 16 x 2
• Character Format: 5 x 8 Dots
• Voltage - Supply: 5.0V
• Operating Temperature: -20°C ~ 70°C
• Character Count X Line: 16 x 2
• Module Size (w X H X T): 38 mm x 80 mm
• Features: Serial LCD
• Fluid Type: STN Positive
• Voltage Rating: 5 VDC
• Operating Temperature Range: - 20 C to + 70 C
• Backlight Type: LED Yellow-Green
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Dot Size: -
• Character Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

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.
To define a custom character, you will send a total of 9 bytes to the Serial LCD. The first byte needs to
be a valid define-custom-character command (Dec 248 to 255) and must be followed by eight data bytes
that define the pixels of the character. The Serial LCD will always use the next eight bytes it receives to
set the pixels of the character. The data bytes define the character starting at the topmost row of pixels,
as shown in the example code.
BASIC Stamp 2 Custom Character Example
Define a custom character using the code example below. First, set the baud rate on your Serial LCD to
19,200. Then, load the code below into your BASIC Stamp 2 and run it. You will see a diamond
character appear on the screen.
' {$STAMP BS2}
TxPin
Baud19200
Copyright © Parallax Inc.
HIGH TxPin
PAUSE 100
SEROUT TxPin, Baud19200, [250]
SEROUT TxPin, Baud19200, [%00000]
SEROUT TxPin, Baud19200, [%00100]
SEROUT TxPin, Baud19200, [%01110]
CON
CON
0
32
Parallax Serial LCDs (#27976, #27977, #27979)
' Set pin high to be a serial port
' Pause for Serial LCD to initialize
' Define custom character 2
' Now send the eight data bytes
' %00000 =
' %00100 =
' %01110 =
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