Matrix Orbital GLT240128 User manual

Chipsmall Limited consists of a professional team with an average of over 10 year of expertise in the distribution
of electronic components. Based in Hongkong, we have already established firm and mutual-benefit business
relationships with customers from,Europe,America and south Asia,supplying obsolete and hard-to-find components
to meet their specific needs.
With the principle of “Quality Parts,Customers Priority,Honest Operation,and Considerate Service”,our business
mainly focus on the distribution of electronic components. Line cards we deal with include
Microchip,ALPS,ROHM,Xilinx,Pulse,ON,Everlight and Freescale. Main products comprise
IC,Modules,Potentiometer,IC Socket,Relay,Connector.Our parts cover such applications as commercial,industrial,
and automotives areas.
We are looking forward to setting up business relationship with you and hope to provide you with the best service
and solution. Let us make a better world for our industry!
Contact us
Tel: [phone] Fax: [phone]
Email & Skype: [email protected]om Web: www.chipsmall.com
Address: A1208, Overseas Decoration Building, #122 Zhenhua RD., Futian, Shenzhen, China
  

GLT240128
Technical Manual
Revision: 1.2

Contents
Contents ii
1 Getting Started 1
1.1 Display Options Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 Connecting to a PC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.1 Connection for Non-USB Modules . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.4.2 Connection for USB Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Installing the Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5.1 MOGD# . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Hardware Information 6
2.1 Communication Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.1 Power/Data Connector for Non-USB modules only . . . . . . . . . . . . . . . . . . 8
2.1.2 USB Connector for USB modules only . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Touchpad Interface Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 DB-9 Connector for Non-USB modules only . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4 Power Through DB-9 Jumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5 Optional USB Header for USB modules only . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.6 Protocol Select Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.7 Filesystem Lock Jumper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.8 Manual Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3 Troubleshooting 15
3.1 The display does not turn on when power is applied. . . . . . . . . . . . . . . . . . . . . . . 15
3.2 The display module is not communicating. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3 The display module is communicating, however text cannot be displayed. . . . . . . . . . . 16
3.4 There is a problem uploading fonts or bitmaps. . . . . . . . . . . . . . . . . . . . . . . . . 16
4 Communications 16
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1 I2C Communication Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.2 I2C Transaction Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4.1.3 Serial Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.1.4 USB Communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.2 Turn Flow Control On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3 Turn Flow Control Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.4 Changing the I2C Slave Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.5 Changing the Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.6 Setting a Non-Standard Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Matrix Orbital GLT240128 ii

5 Fonts 22
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1.1 Font File Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1.2 Creating a Font . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.2 Uploading a Font File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.3 Setting the Current Font . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.4 Font Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.5 Set Box Space Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6 Text 26
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.1.1 Character Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.1.2 Control Characters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.2 Move Cursor Home . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.3 Setting the Cursor Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.4 Setting the Cursor Coordinate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.5 Auto Scroll On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.6 Auto Scroll Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7 Bitmaps 28
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.2 Uploading a Bitmap File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
7.3 Drawing a Bitmap from Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.4 Drawing a Bitmap Directly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8 Bar Graphs and Drawing 30
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.2 Set Drawing Color . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.3 Draw Pixel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.4 Drawing a Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.5 Continue a Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.6 Draw a Rectangle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.7 Drawing a Solid Rectangle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.8 Initializing a Bar Graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.9 Drawing a Bar Graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.10 Initializing a Strip Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.11 Shifting a Strip Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
9 Touchpad 36
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
9.1.1 Region Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
9.1.2 Co-ordinate Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
9.2 Set Touch Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.3 Delete Touch Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.4 Delete All Touch Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.5 Set Touch Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.6 Set Region Reporting Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Matrix Orbital GLT240128 iii

9.7 Set Dragging Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.8 Set Pressure Threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.9 Run Touchpad Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
10 Display Functions 40
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.2 Clear Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.3 Display On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
10.4 Display Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
10.5 Set Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
10.6 Set and Save Brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
10.7 Set Contrast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
10.8 Set and Save Contrast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
11 Filesystem 43
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.1.1 File Upload Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
11.1.2 XModem Upload Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
11.2 Wipe Filesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
11.3 Deleting a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
11.4 Get Filesystem Space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
11.5 Get Filesystem Directory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
11.6 Filesystem Upload . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
11.7 Downloading a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
11.8 Moving a File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
12 Data Security 49
12.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
12.2 Set Remember . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
12.3 Data Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
12.4 Set and Save Data Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
12.5 Dump the Filesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
12.6 Write Customer Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
12.7 Read Customer Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
13 Miscellaneous 53
13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
13.2 Read Version Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
13.3 Read Module Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
14 Command Summary 55
14.1 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
14.2 Fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
14.3 Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
14.4 Bitmaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
14.5 Bar Graphs and Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
14.6 Touchpad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Matrix Orbital GLT240128 iv

14.7 Display Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
14.8 Filesystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
14.9 Data Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
14.10Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
14.11Command By Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
15 Appendix 61
15.1 Optical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
15.2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
15.2.1 Environmental . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
15.2.2 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
15.2.3 Touch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
15.3 Physical Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
15.4 Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
15.5 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
15.6 Contacting Matrix Orbital . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
15.7 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
Matrix Orbital GLT240128 v

1 Getting Started
The GLT240128 is an intelligent graphic LCD display designed to decrease development time by pro-
viding an instant touch screen solution to any project. With the ability to communicate via serial RS-232
protocol at regular and TTL levels as well as USB and I2C, the versatile GLT240128 can be used with virtu-
ally any controller. The ease of use is further enhanced by an intuitive command structure to allow display
settings such as backlight brightness, contrast and baud rate to be software controlled. Additionally, text and
fonts may be uploaded to the display and stored in the on board memory. Finally, simple touch commands
allow for the seemless integration of user control into the display environment.
1.1 Display Options Available
The GLT240128 comes in three backlight options, grey text on a white backlight, white text with a blue
backlight, and standard grey text on a yellow-green backlight . Extended voltage options are also available
to allow you to select the display which will best fit your project needs. Please see table 81 for ordering
information.
Figure 1: GLT240128 Options
Matrix Orbital GLT240128 1

1.2 Accessories
NOTE Matrix Orbital provides all the interface accessories needed to get your display
up and running. You will find these accessories and others on our e-commerce website
at http://www.matrixorbital.com. To contact a sales associate see Section 15.6 for contact
information.
Figure 2: 5V Power Adapter Figure 3: 12V Power Adaptor (-V/-VPT)
Matrix Orbital GLT240128 2

Figure 4: 3ft Mini-B USB Cable Figure 5: Breadboard Cable
Figure 6: Communication & Power Cable Figure 7: Serial Cable
1.3 Features
•240 x 128 pixel graphics display
•Integrated Touchpad Overlay
•Selectable communication protocol, RS-232, TTL, and I2C for Non-USB models; USB only for USB
models
Matrix Orbital GLT240128 3

•128 byte buffered communication
•16 KB flash memory for fonts and bitmaps
•Lightning fast communication speeds, up to 115 kbps for Serial and 100 kbps for I2Cprotocol
•* Use of up to 127 modules on the same 2 wire I2C interface
•Display text using built in or user supplied fonts
•Software adjustable contrast and backlight brightness
•Default 19.2 kbps serial communication speed
•Extended voltage, and efficient power supply available
1.4 Connecting to a PC
The GLT240128 connects seamlessly to a PC and it is an excellent means of testing the functionality
and uploading new fonts and bitmaps. For the Non-USB version, you will require a standard RS-232 9-pin
serial cable such as the one pictured in Figure 7, as well as a modified 5V or 12V power adapter, depending
on the voltage model, such as the ones pictured in Figures 2 and 3. For the USB model, of course, all you
will need is a USB to mini USB cable such as the one in Figure 4.
1.4.1 Connection for Non-USB Modules
In order to connect your Non-USB display to a personal computer follow these easy instructions:
1. Plug the serial cable into the com port you wish to use.
2. Connect the appropraite modified power adapter to a power lead from your PC power supply (you will
have to open your computer case).
3. Connect the serial cable to the DB-9 connector on the back of the display.
4. Connect the appropriate power adapter to the 4-pin connector on the back of the display.
WARNING DO NOT use the standard floppy drive power connector on
the Power/Data Connector, as this will not provide you with the correct
voltage and will damage the display module.
Matrix Orbital GLT240128 4

Figure 8: PC vs Matrix Orbital Display Module Wiring
1.4.2 Connection for USB Modules
In order to connect your USB display to a personal computer simply plug the mini-B USB cable, such
as that shown in Figure 4 from the PC to the USB connector on the display.
1.5 Installing the Software
1.5.1 MOGD#
MOGD# is the latest updated version of MOGD and can be used to manage font and graphics downloads
as well as exercise all of the features of our graphical displays. MOGD# provides a new user friendly
interface as well as many feature enhancements.
To install MOGD# from the Matrix Orbital website, follow the following steps:
1. Go to the website location: http://www.matrixorbital.ca/software/software_graphic/MOGDsharp/
2. Click on "Download Here"
3. Locate the file MogdSharp.zip on your desktop
4. Unzip MogdSharp.zip to a temporary directory using a program such as Winzip
5. Double click on "setup.exe"
Matrix Orbital GLT240128 5

6. Follow the instructions on the screen to complete the installation
7. MOGD# requires the .NET framework 2.0 and will download and install it automatically
After the installation is complete there will be a Matrix Orbital entry under "Start->Programs->Matrix Or-
bital" in the start menu. Click on the ’Mogd Sharp’ entry to run the program.
Be sure to check the information selected in the configuration panel the first time MOGD# is run. Once
this information is entered correctly the program can be used to control all functions of the graphic display.
Port The serial port the display is plugged in to.
Speed The communication speed the display module is set to.
(Default 19,200)
Display Type The type of display (GLT240128)
PCB Revision The revision of the display you are using.
(Found on the back of the PCB).
Figure 9: Mogd Sharp Settings
•Winzip is available as a free download from http://www.winzip.com
2 Hardware Information
Refer to the following diagram for this chapter:
Matrix Orbital GLT240128 6

1Power/Data Connector 5Protocol Select Jumpers
2Touchpad Header 6Filesystem Lock Jumper
3DB9 Connector 7Manual Override Jumper
4Power Through DB9 Jumper
Figure 10: GLT240128 Non-USB
Matrix Orbital GLT240128 7

1USB Connector 4Protocol Select Jumpers
2Touchpad Header 5Filesystem Lock Jumper
3Optional USB Header 6Manual Override Jumper
Figure 11: GLT240128 USB
2.1 Communication Connectors
2.1.1 Power/Data Connector for Non-USB modules only
The Power/Data Connector provides a standard connector for powering the display module. The GLT240128
requires five volts for the standard display module, between nine to fifteen for the wide voltage (V) model,
and between nine to thirty-five volts for the wide voltage with efficient power supply module (VPT). The
voltage is applied through pins one and four of the four pin Power/Data Connector. Pins two and three are
reserved for serial transmission, using either the RS-232 or TTL protocol levels, depending on what has been
selected by the Protocol Select Jumpers.
Matrix Orbital GLT240128 8

Pin 1GND
Pin 2Tx/SDA (I2C data)
Pin 3Rx/SCL (I2C clock)
Pin 4Vcc (see table 78 on page 62)
Figure 12: Power Connector and Pin-out
2.1.2 USB Connector for USB modules only
The USB Connector provides a standard connector for powering and communicating to the USB display
module. As with the non-USB version, the GLT240128-USB requires five volts for the standard display
module as per table 78.
Figure 13: USB Connector for GLT240128
Matrix Orbital GLT240128 9

2.2 Touchpad Interface Connector
The GLT240128 provides a Touchpad InterfaceConnector which allows for the touchpad to be interfaced
to the display. This connector should remain plugged in while the unit is in operation and should not be
tampered with in any way.
Figure 14: Touchpad Interface Connector
2.3 DB-9 Connector for Non-USB modules only
The GLT240128 provides a DB-9 Connector to readily interface with serial devices which use the
EIA232 standard signal levels of ±9V. It is also possible to communicate at TTL levels of 0 to +5V by
setting the Protocol Select Jumpers to TTL. As an added feature it is also possible to apply power through
pin 9 of the DB-9 Connector in order to reduce cable clutter. However, in order to accomplish this you must
set the Power Through DB-9 Jumper.
Matrix Orbital GLT240128 10

Pin 2RX/SCL (I2C clock)
Pin 3TX/SDA (I2C data)
Pin 5GND
Pin 9PWR (Must solder power through DB-9 jumper. See table 78
Figure 15: RS-232 Pin-out
2.4 Power Through DB-9 Jumper
In order to provide power through pin 9 of the DB-9 Connector you must place a solder jumper on the
Power through DB-9 Jumper pictured in Figure 16 below. The GLT240128 allows all voltage models to use
the power through DB-9 option, see table 78 for display module voltage requirements.
Figure 16: Power Through DB-9 Jumper
WARNING Do not apply voltage through pin 9 of the DB-9 connector
AND through the Power/Data Connector at the same time.
NOTE We do not recommend that you use pin 9 (Ring Indicator) of the PC to power the
display module. You will have to make a special DB9 cable.
Matrix Orbital GLT240128 11

2.5 Optional USB Header for USB modules only
The GLT240128 USB version has an optional four pin header for internal USB communications with
host units. This provides the same communication lines as the regular header, albeit in a different form factor
for greater customization. Again, please 78 see for power requirements.
Pin 1GND
Pin 2D+
Pin 3D-
Pin 4Vcc (see table 78 on page 62)
Figure 17: Optional Internal USB Header
2.6 Protocol Select Jumpers
The Protocol Select Jumpers, pictured below in Figure 18, provide the means necessary to toggle the
display module between RS-232 and TTL protocol levels. As a default for Non-USB modules, the jumpers
are set to RS-232 mode with zero ohm resistors on the 232 jumpers. In order to place the display module in
I2C mode you must first remove the zero ohm resistors from the 232 jumpers and then solder the resistors
on to the I2C jumpers, or bridge solder across the pads. The display will now be in I2C mode and have a
default slave address of 0x50 unless the I2C address has been changed. Similarly, in order to change the
display to TTL mode, simply remove the zero ohm resistors from the 232 or I2C jumpers and solder them
to the TTL jumpers. Although RS-232, USB, TTL and I2C are present, only 232/TTL/I2C are for use in the
Non-USB module. For the USB module operation the USB jumpers must be in place. There are three, one
is for power. If you wish to power it up from a non-USB source, you must remove one of the jumpers. The
jumper to remove is the rightmost USB jumper as seen if Figure 19.
Matrix Orbital GLT240128 12

Figure 18: Protocol Select Jumpers for Serial and I2C modules
Figure 19: Protocol Jumpers for USB modules
2.7 Filesystem Lock Jumper
The Filesystem Lock Jumper allows you to lock the filesystem on the GLT240128 so that no fonts or
bitmaps can be either written or deleted from the on board memory. This feature is useful in order to protect
data integrity of production units, if protection of other settings is required see Section 12
To lock the filesystem, solder a zero ohm resistor or use a solder jumper pictured in Figure 20 below.
Matrix Orbital GLT240128 13

Figure 20: Filesystem Lock Jumper
2.8 Manual Override
The Manual Override is provided to allow the GLT240128 to be reset to some of the factory defaults.
This can be particularly helpful if the display module has been set to an unknown baud rate or I2C and you
are no longer able to communicate with it. If you wish to return the module to its default settings you must:
1. Power off the display module.
2. Place a Jumper on the Manual Override pins, as pictured below.
3. Power up the display module.
4. The display module is now set to its default values listed below in table 1.
5. Edit and save settings.
Figure 21: Manual Override Jumper
Matrix Orbital GLT240128 14