Matrix Orbital LCD2041 User manual

LCD2041
Technical Manual
Revision: 2.0

Contents
Contents ii
1 Introduction 1
1.1 What to Expect From the LCD2041 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 What Not to Expect From the LCD2041 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 SetupforTesting ........................................ 1
1.4 TryingouttheLCD2041 .................................... 2
2 Connections 2
2.1 ConnectorPinout ........................................ 2
2.1.1 PowerConnection ................................... 3
2.1.2 FiveVoltModules ................................... 4
2.1.3 Wide Voltage Range Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.4 Applying Power through the DB-9 Connector . . . . . . . . . . . . . . . . . . . . 6
2.2 RS-232Communications.................................... 6
2.2.1 DB9Connections.................................... 6
2.2.2 Alternate Serial Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.3 TTLcommunications ................................. 8
2.2.4 Configuring RS-232 and I2C ............................. 8
2.3 I2CCommunications ...................................... 10
2.3.1 ACK .......................................... 10
2.4 GeneralPurposeOutput..................................... 11
3 Displaying Text 12
3.1 General ............................................. 13
3.2 ThebuiltinCharacterFont................................... 13
3.3 WritingTexttotheDisplay................................... 14
3.4 TextCommands......................................... 14
3.4.1 Auto line wrap on (254 67) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4.2 Auto line wrap off (254 68) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4.3 Autoscrollon(25481) ................................ 14
3.4.4 Autoscrolloff(25482) ................................ 14
3.4.5 Set cursor position (254 71 [column] [row]) . . . . . . . . . . . . . . . . . . . . . . 15
3.4.6 Send cursor home (254 72) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.7 Turn on underline cursor (254 74) . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.8 Turn off underline cursor (254 75) . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.9 Turn on block (blinking) cursor (254 83) . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.10 Turn off block (blinking) cursor (254 84) . . . . . . . . . . . . . . . . . . . . . . . 15
3.4.11 Cursorleft(25476)................................... 15
3.4.12 Cursorright(25477).................................. 16
Matrix Orbital LCD2041 ii

4 Bar Graphs and Special Characters 16
4.1 CommandList ......................................... 16
4.1.1 Initialize wide vertical bar graph (254 118) . . . . . . . . . . . . . . . . . . . . . . 16
4.1.2 Initialize narrow vertical bar graph (254 115) . . . . . . . . . . . . . . . . . . . . . 16
4.1.3 Draw vertical bar graph (254 61 [column] [height]) . . . . . . . . . . . . . . . . . . 16
4.1.4 Initialize horizontal bar graph (254 104) . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.5 Draw horizontal bar graph (254 124 [column] [row] [dir] [length]) . . . . . . . . . . 17
4.1.6 Initialize large digits (254 110) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.7 Place large digit 254 35 [col] [digit] . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.8 Define custom character (254 78 [c] [8 bytes]) . . . . . . . . . . . . . . . . . . . . 17
5 Miscellaneous Commands 19
5.1 CommandList ......................................... 19
5.1.1 Cleardisplay(25488) ................................. 19
5.1.2 Set contrast (254 80 [contrast]) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1.3 Backlight on (254 66 [minutes]) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1.4 Backlightoff(25470) ................................. 19
5.1.5 General purpose output off (254 86) . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.1.6 Set backlight brightness (254 153 [brightness]) . . . . . . . . . . . . . . . . . . . . 20
5.1.7 General purpose output on (254 87) . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5.1.8 Readmoduletype ................................... 20
6 Appendix; Command Summary 20
6.1 General ............................................. 20
6.2 IssuingCommands ....................................... 20
6.3 OnNumbers........................................... 21
6.3.1 ASCIICharacters.................................... 21
6.4 TextCommands......................................... 22
6.5 Bar Graphs and Special Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.6 MiscellaneousCommands ................................... 25
7 Appendix: Specifications 26
7.1 Specifications.......................................... 26
7.2 Options ............................................. 28
8 Appendix: Glossary 28
Matrix Orbital LCD2041 iii

1 Introduction
The LCD2041 comes equipped with the following features;
•20 column by 4 line text display
•Built in font with provision for up to 8 user defined characters
•Speeds from 1200 bps to a lighting fast 19.2 Kbps over RS-232
•Communication over RS-232 or I2C
•Software controlled contrast
•Backlight with configurable time out setting up to 180 minutes
•One general purpose output for a variety of applications
•Horizontal or Vertical bar graphs
•Variable power options, +5V or +8V to +15V
•Extended temperature option
•Fits Matrix Orbital’s Dual PC Bay insert without any modifications
1.1 What to Expect From the LCD2041
The LCD2041 is designed as the display unit for an associated controller. The controller may be anything
from a single board, special purpose micro-controller to a PC, depending on the application. This controller
is responsible for what is displayed on the screen of the display.
The display provides a simple command structure to allow text and bar graphs to be displayed on the
screen. Text fonts are built in, and use standard ASCII mapping. Provision is made for up to 8 user defined
characters.
The screen is backlit for low light situations. Backlighting may be turned on or off under program
control. Contrast is adjustable to compensate for differing lighting conditions and viewing angles.
A general purpose output allows the controller to switch an electronic or electro-mechanical device by
issuing commands to the display unit. This can be used for controlling LEDs, relays, etc.
1.2 What Not to Expect From the LCD2041
The display does not include bitmap graphics capability, except that permitted by defining special char-
acters. The display does not include a keypad interface.
1.3 Setup for Testing
Before setting up the application the user may want to try out the display. This is easily done with a PC.
If not equipped with a dual bay PC mounting kit, the following will be required;
•A 4-pin power connector of the type used to connect 3.5” floppy drive. Take care not to connect the
display to an unmodified spare power connector in a PC
•A spare RS-232 port. (Either COM1 or COM2)
•A 5V power supply. For wide voltage models, an 8 - 15 V supply will be required
•A 9 or 25 pin RS-232 serial cable. If using a 25 conductor cable, a 9 to 25 pin adapter will be required
Matrix Orbital LCD2041 1

Figure 1: Connections for Testing
1. Refer to the Figure above for the following steps.
2. Wire the connector to the power supply. On most connectors the RED lead will go to +5V and the
BLACK lead to GND.
NOTE The Manufacturer’s Warranty becomes void if the unit is subjected to over-voltage
or reversed polarity.
3. Connect the display to the PC using the serial cable and adapter if required. Make sure the RS-232
cable includes the required ground lead. There must be no voltage differential between the RS-232
ground and the power supply ground.
4. Connect the power connector, making sure that the +5V goes to V+ . Turn on the power; the display
backlight should come on and a blinking cursor at the top left should appear.
1.4 Trying out the LCD2041
The unit should be connected to power and the PC and backlight should be on. To experiment with
typing text, run a PC program such as Display Tuner or AlphaDemo. Make sure it’s configured to use the
correct port. Set the baud rate to 19,200.
To exercise some of the other features of the display, a program (in any convenient language such as
Basic or C) will need to be written in order to issue the required command strings. Most terminal programs
are unable to issue the 0xFE character needed as a command prefix.
2 Connections
2.1 Connector Pinout
Refer to the Figure below for this chapter.
Matrix Orbital LCD2041 2

Figure 2: Electrical Connections
The display has three connectors;
Table 1: Connectors & Functions
Connector Function
2 pin General purpose output
4 pin Power and I2C communication
DB-9F RS-232/power
2.1.1 Power Connection
Power is applied via pins 1 and 4. Power requirement for standard units is +5 VDC ±0.25V . Units with
the wide voltage range option require 8 - 15 VDC.
WARNINGS
•Do not apply any power with reversed polarization. Do not apply
any voltage other than the specified voltage. Do not use any cables
other than the cables supplied by Matrix Orbital, unless aware of
the modifications required. Do not apply voltage to the DB-9 con-
nector AND power connector Do not apply more than +5Vdc to
pin #9 on the DB-9 connector.
Matrix Orbital LCD2041 3

Connector pinout is as follows;
Figure 3: Power Connector
Table 2: Pinout Connections
Pin 4 Ground
Pin 3 SDA (I2C data) / Rx
Pin 2 SCL (I2C clock) / Tx
Pin 1 Vdc
2.1.2 Five Volt Modules
If the display is used in a PC it is tempting to plug a spare power connector into the unit. Don’t do this!
Wiring for the PC power connector and that required for the display are different.
Figure 4: Wiring for 5V Modules
Matrix Orbital is equipped to supply an adapter cable designed to use with the LCD2041 when it’s
installed in a PC. The cable is wired as shown in the Figure below.
NOTE This cable does not provide connections for I2C.
Matrix Orbital LCD2041 4

Figure 5: Five Volt Power Cable
2.1.3 Wide Voltage Range Modules
NOTE Do not use this cable unless the display module has the "Wide voltage range"
option. Use of the 12 volt power cable with 5 volt modules will damage the module.
The 12 volt power cable is designed for use with wide voltage range display modules mounted in a PC.
Wiring required for the 12 volt power connector is shown in the Figure below.
Figure 6: Wiring for 12 Volt Modules
Matrix Orbital is equipped to supply an adapter cable designed to use with the display module when it’s
installed in a PC. The cable is wired as shown in the Figure below.
Figure 7: Twelve Volt Power Cable
Matrix Orbital LCD2041 5

2.1.4 Applying Power through the DB-9 Connector
Power may be provided to the module by pin 9 of the DB-9 connector instead of through the 4-pin SIP.
If power is to be applied using the DB-9, it must be a regulated 5Vdc supply.
NOTE This applies to wide voltage units, V and VPT extensions, as well as to standard
5 volt units.
Figure 8: DB-9 Power
To use pin 9 as the power source, the user must solder the 5 volt jumper pad beside the DB-9 connector.
WARNING Application of a voltage to pin 9 greater than 5.25 volts
may cause immediate destruction of unit and void the Manufacturer’s
Warranty.
2.2 RS-232 Communications
The RS-232 connector on the PC cable is wired so that a standard ’straight through’ 9 pin D-sub cable
may be used to connect the module to a standard serial port such as COM ports on PCs. Please note that this
device complies with the EIA-232 standard in that it uses signal levels from ±12V to ±12V and can be
converted to TTL levels as well. The display is set at 19.2Kbps default speed. Other settings are;
•8 bits, no parity, 1 stop bit.
2.2.1 DB9 Connections
A standard DB-9F is provided for RS-232 communications. Power may also be supplied via this con-
nector if desired.
Matrix Orbital LCD2041 6

Figure 9: RS-232 and Power Connector
Table 3: RS-232 Pinout
Pin Number Direction Description LCD Host
2 Data from LCD Data out (LCD Tx Rx
3 Data to LCD Data in (LCD) Rx Tx
5 - Ground gnd gnd
2.2.2 Alternate Serial Connection
An optional alternate connection header is provided to allow one cable for data and power. Two jumpers
will have to be set into the RS-232 position above the DB-9 connector.
Figure 10: RS232 Configuration
Connector pinout is as follows;
Matrix Orbital LCD2041 7

Pin 4 Ground
Pin 3 Rx
Pin 2 Tx
Pin 1 Vdc
Figure 11: Power Connector
2.2.3 TTL communications
The display can be talked to at TTL (logic 0V to +5V) levels. The following three jumps will need to be
modified as shown in figure below. This will allow TTL communications through the 4-pin SIP header or
the DB9 connector.
Figure 12: TTL Communications
2.2.4 Configuring RS-232 and I2C
RS-232 baud rate and I2C address are configured by means of jumpers.
Matrix Orbital LCD2041 8

Figure 13: RS-232 Jumpers
The module is supplied with jumpers J1 and J2 installed, which gives an RS-232 baud rate of 19200 and
an I2C address of 0x5C.
•RS-232 port: J0, J1, J2 - control baud rate. RS-232 format is 8N1, 8 bits, no parity, one stop bit
•I2C port: J0, J1, J2, J3 - sets slave peripheral address
Table 4: Serial Baud Rates
Baud Rate Slave Address J3 J2 J1 J0
1200 50H out out out out
52H out out out in
2400 54H out out in out
56H out out in in
9600 58H out in out out
5AH out in out in
19200 5CH out in in out
5EH out in in in
1200 60H in out out out
62H in out out in
2400 64H in out in out
66H in out in in
9600 68H in in out out
6AH in in out in
19200 6CH in in in out
6EH in in in in
Matrix Orbital LCD2041 9

2.3 I2C Communications
I2C communications runs at 100Kbps and supports up to 16 units on a single communications line. The
I2C data line operates on 5 volt CMOS levels.
2.3.1 ACK
The idea of ACK is to indicate when the data has been received correctly. ACK does not indicate data
incorrectly received. ACK simply fails to indicate when data is correctly received. Clearly, this is of limited
usefulness and even less so with Matrix Orbital modules. Matrix orbital modules are not capable of failing
to acknowledge an incorrectly received byte in response to that bytes transition. They are only capable of
failing to acknowledge the bytes following the byte, which was not received. To fully understand the reasons
for this one needs to understand something about how a Matrix Orbital module processes data. Basically the
reason why a Matrix Orbital module might fail to receive a byte correctly is that it was unable to process the
byte previous before the failed byte was transmitted. Because the module cannot possibly know that it would
be unable to store the byte before the next byte was received it cannot know to not ACK. The reason for this
situation in deference to situations one might be familiar with (i.e., memory chips, etc) is that the Matrix
Orbital module employs a micro-processor to perform these data storage functions. A memory chip takes
care of these things entirely with in hardware subsystems that operate at the same speed as the transmission
themselves.
The display uses a standard Phillips 7bit address as defined by Phillips. However, Matrix Orbital specifies
I2C address in 8bits. The 8th bit, or least significant bit, LSB or Low Order Bit of the 8bit address is a read
/ write bit. If we take a standard Phillips 7bit address of 45hex this would be in binary, 1000101. This is
7bits. Matrix Orbital would describe the Phillips I2C address of 45hex as 8Ahex. The read address would
be 8Bhex.
For more information on Phillips I2C please visit;
http://www.ping.be/~ping0751/i2cfaq/i2cindex.htm
And for more information specific to our displays visit;
http://www.lcdforums.com/forums/viewtopic.phpt=910
To communicate by I2C two jumpers have to be set into the I2C position above the DB-9 connector.
Figure 14: I2C Communications
Connector pinout is as follows;
Matrix Orbital LCD2041 10

Pin 4 Ground
Pin 3 SDA (12C Data)
Pin 2 SLC (I2C Clock)
Pin 1 Vdc
Figure 15: Power Connector
2.4 General Purpose Output
The display has a general purpose output which can be used to control relays or other electronic devices.
This allows external devices to be turned on or off using your PC or controller and software commands. The
+ terminal is connected to the module positive supply, the - terminal is connected through a 240ohm current
limiting resistor and the electronic switch to ground.
Figure 16: General Purpose Output
Maximum allowable current is 20mA, which is enforced by the current limiting resistor. If the device
being switched has a resistance of 240ohms or more the corresponding resistor may be shorted. Solder a
small jumper wire or wirewrap wire between the two feed through holes.
Matrix Orbital LCD2041 11

Figure 17: Bypassing 240 ohm Resistor
NOTE The GPOs do not have any over current or over / under voltage protection so care
must be taken when using them. For instance if the external device is a relay it must be fully
clamped using a diode and capacitor to absorb any generated back electro-motive force or
“EMF”.
Figure 18: Clamping a Relay
3 Displaying Text
This chapter describes the various text-display commands in detail. Before issuing commands to the
LCD2041 please read sections 6.2 and 6.3.
Matrix Orbital LCD2041 12

3.1 General
Text is displayed on the display using the built in 5x7 dot matrix font, in addition to up to 8 user defined
characters.
3.2 The built in Character Font
The display includes a built in 5x7 dot matrix font with the full range of ASCII characters plus a variety
of extended characters, as shown in the Figure below.
Figure 19: Character Set
In addition to the built in characters, users may define up to 8 special characters which, once defined,
occupy positions 0x00 to 0x07 in the above chart. The display does not have provision to download other
Matrix Orbital LCD2041 13

fonts.
3.3 Writing Text to the Display
When the display receives a character, it displays that character at the position currently defined. The
next character sent to the module then advances to the following position on the display. Characters are
drawn using the built in font, and only characters defined in the font are actually displayed. Characters that
are not defined by the built in font print as a space. The position where text is to be inserted is a character
location stored in the display’s volatile memory and maintained internally by the display’s firmware. This
position is manipulated by the commands shown in the following section.
3.4 Text Commands
In this section commands are identified by their names and decimal values.
3.4.1 Auto line wrap on (254 67)
Enables automatic line wrapping. This is not ’word wrapping’ and wraps may occur in the middle of a
word. If auto line wrap and auto scroll are both off (default) text will wrap from line 1 to line 3 then 2 then
4. Factory default is OFF.
3.4.2 Auto line wrap off (254 68)
Disables automatic line wrapping.
3.4.3 Auto scroll on (254 81)
When auto scrolling is on the display shifts the entire display’s contents up to make room for a new line
of text when the text reaches the scroll position at the bottom right character position.
3.4.4 Auto scroll off (254 82)
When auto scrolling is disabled, text will wrap to the top left corner of the display area. Existing text in
the display area is not erased before new text is placed. A series of ’spaces’ followed by a “Cursor home”
command may be used to erase the top line of text.
Matrix Orbital LCD2041 14

3.4.5 Set cursor position (254 71 [column] [row])
This command sets the cursor position (text insertion point) to the [column] and [row] specified. Columns
have values from 1 to 20 (0x01 to 0x14) and rows have values of 1 to 4 (0x01 to 0x04).
3.4.6 Send cursor home (254 72)
This command moves the cursor position (text insertion point) to the top left of the display area.
3.4.7 Turn on underline cursor (254 74)
Turns on the underline cursor. The cursor shows the current text insertion point. Both underline and
blinking cursors may be turned on or off independently. The cursor is off by default.
3.4.8 Turn off underline cursor (254 75)
Turns off the underline cursor. Does not affect the blinking block cursor.
3.4.9 Turn on block (blinking) cursor (254 83)
Turns on the blinking block cursor. The cursor shows the current text insertion point. Both blinking and
underline cursors may be turned on or off independently. The cursor is off by default.
3.4.10 Turn off block (blinking) cursor (254 84)
Turns off the blinking block cursor. Does not affect the underline cursor.
3.4.11 Cursor left (254 76)
Moves the cursor one position to the left but does not erase any character that may be in that position.
Note that this command moves the text insertion point even if the cursor is turned off.
NOTE A ’destructive backspace’ which erases the character to the left of the original
position, may be done by issuing the following sequence: cursor left, space, cursor left.
Matrix Orbital LCD2041 15

3.4.12 Cursor right (254 77)
Moves the cursor one position to the right but does not erase any character that may be in that position.
This command moves the text insertion point even if the cursor is turned off.
4 Bar Graphs and Special Characters
The display includes the ability to draw bar graphs, either horizontally or vertically, large numbers, and
allows users to define up to eight special characters. Eight characters (ASCII values 0x00 to 0x07) are set
aside for use with bar graphs, user defined characters, and large digits. Since the same 8 characters are used
for each function, the functions may not be used simultaneously. The characters may be defined or redefined
at any time by issuing the commands shown in this section. Once defined, they may be used either by means
of the bar graph commands, or by simply issuing one of the ASCII values 0x00 to 0x07 which is not prefixed
by the command byte, 254.
4.1 Command List
4.1.1 Initialize wide vertical bar graph (254 118)
This command defines the 8 special / user characters to be blocks suitable for use in drawing wide
vertical bar graphs, such as 5 pixels. Any previously existing definitions will be lost. Once this command
has been issued, any number of vertical bar graphs may be drawn unless the characters are redefined by
another command.
4.1.2 Initialize narrow vertical bar graph (254 115)
This command defines the 8 special / user characters to be blocks suitable for use in drawing narrow
vertical bar graphs, such as 2 pixels. Any previously existing definitions will be lost. Once this command
has been issued, any number of vertical bar graphs may be drawn unless the characters are re-defined by
another command.
4.1.3 Draw vertical bar graph (254 61 [column] [height])
Draws a vertical bar graph in [column] having a height of [height] pixels. The height may range from
0 to 20 (0x00 to 0x14) pixels. The necessary characters must first be initialized by either of the commands
shown in section 5.1.1 or 5.1.2, which will determine the width of the graph drawn. Graph may be erased
by drawing a bar graph of height = 0 in the same column.
Matrix Orbital LCD2041 16

4.1.4 Initialize horizontal bar graph (254 104)
This command defines the 8 special / user characters to be blocks suitable for use in drawing horizontal
bar graphs. Any previously existing definitions will be lost. Once this command has been issued, any number
of horizontal bar graphs may be drawn unless the characters are redefined by another command.
4.1.5 Draw horizontal bar graph (254 124 [column] [row] [dir] [length])
Draws a horizontal bar graph in [row] starting at [column] with a length of [length] pixels. [row] may
have a value of 0x01 or 0x02, column may range from 0x01 to 0x14 and length may be from 0x00 to 0x64 (0
to 100) if the graph can extend the full width of the screen. Each column is 5 pixels wide, as spaces between
the columns don’t count.
[dir] specifies the direction: 0x00 goes from left to right, 0x01 goes from right to left.
4.1.6 Initialize large digits (254 110)
This command defines the 8 special / user characters to be blocks suitable for use in drawing large digits.
Any previously existing definitions will be lost. Once this command has been issued, any number of large
characters may be placed until the characters are redefined by another command.
4.1.7 Place large digit 254 35 [col] [digit]
This command allows the large digits to be drawn on the display screen. Numbers of almost full display
height may be placed along side regular text on four row displays. The column number has a maximum
value which is less than the display width because the digits are all three columns wide.
Before using this command the “Initialize large digits” command must be issued to define the blocks
necessary to make up the digits. If regular text and large digits are mixed on one screen, the user should
always set the display cursor position before placing regular text because the creation of a large digit will
leave the cursor position to the bottom right of the large digit and not at the last regular text write position.
[col] can have values from 0x01 to 0x12 (1 to 18). [digit] has values from 0x00 to 0x09 (0 to 9).
4.1.8 Define custom character (254 78 [c] [8 bytes])
The display allows up to 8 user defined ’custom’ characters. These characters occupy the first 8 (0x00
to 0x07) places in the character set.
Custom characters occupy a 5x8 pixel matrix. Built in characters are 5x7: the bottom row of pixels is
normally reserved for the underline cursor. The underline cursor should be turned off if the bottom row of
pixels forms part of a custom character.
The characters are defined by issuing the command 254 78 [c] followed by 8 bytes to define the character.
[c] is the character number (0x00 to 0x07). The 8 bytes are mapped as shown below;
Matrix Orbital LCD2041 17