User’s Manual
BPI-216 • v1.2 • 07/00 • pg 1
BPI-216 Serial LCD Modules
BPI-216 LCD modules combine a serial interface with a 2-line by 16-character LCD. The combination
receives serial data at 2400 or 9600 baud (switch selectable) and displays it on the LCD.
The unit has two modes:
text
and
instruction.
It defaults to text mode; any data received appears on
the screen. Send the string “HELLO” and “HELLO” appears on the LCD. To distinguish text from
instructions (e.g., clear screen, position cursor, etc.), the interface looks for an instruction prefix (ASCII
254). The byte following this prefix is treated as an instruction. After the instruction code, the unit
returns to text mode.
This product replaces BPK-series serial LCD modules, which function identically. The primary difference
is in the physical layout of the circuit board, which has been optimized for 2x16 LCDs. The LCD Serial
®
board (without an LCD; BPK-000) remains available for other applications.
Table of Contents
Location of Connectors and Controls........................................................................................2
Quick Checkout and Contrast Adjustment ................................................................................2
LED Backlight............................................................................................................................2
Setting the Baud Rate ...............................................................................................................3
Hookup for Use .........................................................................................................................3
Basic Operation.........................................................................................................................3
Positioning the Cursor...............................................................................................................4
Off-Screen Memory...................................................................................................................4
Defining Custom Symbols.........................................................................................................5
Program Examples....................................................................................................................7
Dimensions ...............................................................................................................................8
Differences from BPK- series....................................................................................................8
Specifications ............................................................................................................................8
Important Notes on Handling, Installation, Mounting..........................................................8
Disclaimer of Liability
Scott Edwards Electronics, Inc. is not responsible for any special, incidental, or consequential damages resulting
from any breach of warranty, or under any legal theory, including lost profits, downtime, goodwill, damage to or
replacement of equipment or property, and any costs or recovering, reprogramming, or reproducing of data
associated with the use of the hardware or software described herein.
Warranty
Scott Edwards Electronics, Inc. warrants this product against defects in materials and workmanship for a period
of 90 days. If you discover a defect, we will, at our option, repair, replace, or refund the purchase price. Return
the product with a description of the problem. We will return your product or its replacement via standard shipping.
Expedited shipping is available at the customer’s expense.
• Note: Abusing the module, operating it outside specified limits of power or temperature, or attempting to repair
or modify it, voids this warranty. See figure 1 (page 2) and specifications/notes (page 8).
Trademarks and Copyrights
LCD Serial Backpack
®
is a registered trademark of Scott Edwards Electronics, Inc.; BASIC Stamp
®
is a registered
trademark of Parallax Inc. All trademarked names referenced herein are the property of their respective holders.
This manual in its entirety is copyright Scott Edwards Electronics, Inc., 1994—2000.
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: 520-459-0623 • www.seetron.com
User’s Manual
BPI-216 • v1.2 • 07/00 • pg 2
Location of Connectors and Controls
Figure 1 shows the major features and configuration options of the BPI-216 circuit board. Note: The
Backlight switch has no effect on non-backlit models. The model (-L for backlit, -N for non-) is marked
at the lower-left corner of the interface board.
Back of LCD
Module
Model
N[x] = non-backlit
L[x] = LED backlit
(backlit shown)
Contrast
(darker)
+5V
GND
Serial data
1
2
Duplicate +5V and GND
connections (see text)
BPS switch
(down = 2400; up = 9600)
BACKLIGHT switch
(down = off; up = on)
EXTERNAL Backlight switch
(see figure 2 for details)
Do not reverse +5V and GND, even momentarily.
Reversed power will destroy the electronics.
Do not exceed 5.5V into +5V.
Overvoltage will damage the unit or shorten its life.
Figure 1. Back (interface-side) view of BPI-216.
Quick Checkout and Contrast Adjustment
You can test the unit for proper operation without a computer/serial port. Temporarily connect the
serial input to one of the +5 terminals of J1, then connect power to +5 and GND. The LCD will display
a test message.
The contrast control is usually set fully clockwise at the factory. This setting may be too dark. Use a
small, flat-blade screwdriver to adjust the contrast control.
LED Backlight
On models equipped with an LED backlight (marked
L[x]
in the lower left corner of the interface board),
you may turn on the backlight by setting the
BL
switch ON. The backlight will be on whenever power
is applied. There is also a pair of solder pads near the backlight switch (see figure 1 above) to allow
you to control the backlight with an external switch or circuit. Figure 2 below shows the wiring of the
backlight and the pads.
Pads on pcb
(close up section of
fig. 1 above)
Equivalent Circuit
+5V
LEDs
(Vforward≈ 4V)
27Ω
pad 1
BL
switch
1
2
pad 2
1
2
NPN
control with
5V logic (1=ON)
press-to-light
pushbutton
Applications
(Built-in BL switch must be OFF)
Figure 2. Connecting
external circuits to
control the backlight.
470–
1k
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: 520-459-0623 • www.seetron.com
User’s Manual
BPI-216 • v1.2 • 07/00 • pg 3
Setting the Baud Rate
Set the BPS switch down for 2400 baud; up for 9600. At either rate, the serial characteristics are no
parity, 8 data bits, 1 stop bit. For more information on serial transmission, see the application note:
www.seetron.com/ser_an1.htm.
NOTE:
The interface reads the BPS switch only at startup. Change the BPS setting only with the
power off. The Backlight (BL) may be turned on or off at any time.
Hookup for Use
Figure 3 shows how to connect the BPI-216 to PCs and BASIC Stamp computers in order to run the
example programs presented later in this manual. Refer to figure 1 or the markings on the interface
for the locations of +5, GND and SER(ial in).
The 5-pin connector has two extra pins for +5 and GND. These pins are arranged in a
pallindrome
layout. If you make a matching 5-pin connector, the connections will always line up properly regardless
of connector orientation. Ready-made wiring harnesses and instructions for making your own hookups
are available from www.seetron.com. If you do not need a removable connector, you may wire-wrap or
solder wires directly to the header posts.
PC Serial (comm) Port
BPI-216
Stamp
SER
DB-9 female
(solder side)
1
2
3
4
5
BASIC Stamps
BPI-216
GND
+5
SER
GND
+5
6
7
8
9
power
supply
GND (Vss)
+5V (Vdd)
I/O pin 0 (P0)
+5
Note: the gray lines are loopback connections that may
be required if the PC software/hardware expects
handshaking. They may be omitted in most cases.
Figure 3. Connecting to PC serial port, BASIC Stamps.
Basic Operation
Once the BPI-216 is properly connected and configured to match the baud rate of the computer/program
that will be talking to it serially, data sent to it will appear on the display. For example, if you send
“Hello” then “Hello” appears on the display. The cursor (printing position) automatically moves from
left to right.
You can also send instructions to the BPI-216. To identify a particular byte as an instruction, precede
it with the
instruction prefix
character, ASCII 254 (0FE hex, 11111110 binary). The interface treats the
byte immediately after the prefix as an instruction, then automatically returns to data mode.
Example: The clear-screen instruction is ASCII 1. To clear the screen, send <254><1> (where the <>
symbols mean single bytes set to these values, not text as typed from the keyboard). Table 1 lists the
LCD instructions.
Startup Time
When the BPI-216 is first powered up, it requires about 750 milliseconds (ms) to initialize the LCD
and get ready to receive data. Programs should wait about a second after powerup before sending data
to the BPI-216.
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: 520-459-0623 • www.seetron.com
User’s Manual
BPI-216 • v1.2 • 07/00 • pg 4
Table 1. LCD Instructions
Instruction/Action
Clear Screen
Scroll display one character left (all lines)
Scroll display one character right (all lines)
Home (move cursor to top/left character position)
Move cursor one character left
Move cursor one character right
Turn on visible underline cursor
Turn on visible blinking-block cursor
Make cursor invisible
Blank the display (without clearing)
Restore the display (with cursor hidden)
Set cursor position (DDRAM address)
Set pointer in character-generator (CG) RAM
Code
1
24
28
2
16
20
14
13
12
8
12
128 + addr
64 + addr
These instructions take more than 1 ms for the LCD to execute. At 9600 bps, either pause
1ms after these instructions or follow them with <254><128> (where <#> means a byte
set to #). At 2400 bps, no pause or extra instruction is required.
Advanced LCD users: These are the actual LCD instruction codes. When the interface receives the instruction prefix, it clears
the register select (RS) bit. The next received byte is written to the LCD with RS low. After writing that byte, it returns RS high
(normal data mode). This means that you can send any valid LCD instruction through the interface. Since the interface intializes
the LCD at startup, you must
not
send any initialization instructions. If you did not understand the preceding, don’t worry. You
don’t need to know any of this to use this product. The info may be handy to advanced users adapting programs written to drive
the BPI-216 to applications that drive an LCD directly through its parallel interface.
Positioning the Cursor
You can position the cursor anywhere on the screen by sending the proper instruction. Figure 4 shows
the layout of the 2x16 LCD screen with the cursor-positioning instruction for each character location.
Character
LINE 1
LINE 2
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143
192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
To position the cursor, send the instruction-prefix byte, ASCII 254, followed by the set-position
byte value. For example, to move to line 2, character 4, send <254><196>. Note: <#> means
a byte set to the value #. See program examples.
Figure 4. Cursor positioning.
Off-Screen Memory (No Line Wrap)
When you print past the end of a line, the next 24 characters do not show up on the screen. They are
not lost, they are in an off-screen memory area. All alphanumeric LCD modules have 80 bytes of
memory, arranged appropriately for a 2x40 screen. On LCDs with smaller screens (such as this 2x16),
text printed past the end of a visible line goes into memory, but can’t be seen on the screen. Use cursor-
positioning instructions to print to a particular location on the display. Or deliberately print in off-
screen memory to temporarily hide text, then send scroll-left instructions to reveal it.
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: 520-459-0623 • www.seetron.com
User’s Manual
BPI-216 • v1.2 • 07/00 • pg 5
Defining Custom Symbols
Most of the LCD characters (figure 6) cannot be changed because they are stored in ROM. However,
the first eight symbols, corresponding to ASCII 0 through 7, are stored in RAM. By writing new values
to the character-generator (CG) RAM, you can alter these characters. Changing a symbol is easy; just
point to the beginning of the symbol’s RAM location, then write eight bytes whose bits form the desired
pattern. Then position the cursor onto the screen. See figure 5.
Manipulating custom characters allows you to create special effects, like simple animations. See serial
display application notes at www.seetron.com for examples and a handy visual character editor.
Bitmap Layout
bit 4
bit 3
bit 2
bit 1
bit 0
Symbol Locations
Byte Values
Example: Loading the Symbol
To load the arrow shown at left to symbol 3,
a program would send the following bytes to
the LCD:
<254><88>
<0><4><2><31>
<2><4><0><0>
<254><128>
' Point to symbol 3
' Send the bit
' pattern
' Move cursor back
' to the screen
byte 0
byte 1
byte 2
byte 3
byte 4
byte 5
byte 6
byte 7
binary
xxx00000
xxx00100
xxx00010
xxx11111
xxx00010
xxx00100
xxx00000
xxx00000
decimal
0
4
2
31
2
4
0
0
ASCII
Code
0
1
2
3
4
5
6
7
Base
Address
64
72
80
88
96
104
112
120
<#> means a byte set to the value #.
See the program examples.
Figure 5. Defining custom symbols.
0
0
1
2
3
4
5
6
7
32
40
48
56
64
72
80
88
96
104 112 120 160 168 176 184 192 200 208 216 224 232 240 248
NOTE: Custom characters occupy ASCII 0—7
Backpack loads patterns shown at startup.
ASCII 8—31 repeat the custom characters
ASCII 128–160 are blanks
To find the ASCII code for a given character, add the row and column numbers.
For example, capital D is in the column marked 64 in row 4, so its ASCII code is
68. Use the reverse procedure to determine the symbol for a given code. For
example, ASCII code 244 produces the symbol
Ω,
found at colum 240, row 4.
Figure 6. LCD character set.
Scott Edwards Electronics, Inc.
1939 S. Frontage Road, Suite F, Sierra Vista, AZ 85635 USA
ph: 520-459-4802 • fax: 520-459-0623 • www.seetron.com
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