Matrix Orbital GLC24064 - Manual (Page 16)

• Finally, you may reset the display to it’s default settings using the Manual Override Jumper, see
Section 2.5 on page 9.
3.3 The display module is communicating, however text cannot
be displayed.
• The cause of this is often that no font has been loaded onto the display. To load a font onto the display
see Section 4.2.1 on page 16.
• Another common cause may be that the contrast settings have been set to low. The solution to this
problem is to adjust the contrast settings, the default setting that will work in most environments is
128.
NOTE Optimal contrast settings may vary according to factors such as temperature, view-
ing angle and lighting conditions.
3.4 There is a problem uploading fonts or bitmaps.
• First, ensure that you can communicate to the display. A good test is to use a PC, with MOGD#
installed, to connect to the display. See Section 1.4 on page 3 for setting up a PC to test the GLC24064.
• Second, unsure that the File System Lock Jumper has not been set. See Section 2.6 on page 9.
• Third, please ensure that the display module’s memory is not full. The GLC24064 has 16 Kb of
memory for fonts and bitmaps.
NOTE If you are unable to resolve any issue please contact Matrix Orbital. See 15.6 on
page 57 for contact information.
4 Communications
4.1 Introduction
The commands listed in this chapter describe how to configure data flow on the .
4.1.1 I 2 C Communication Summary
The is capable of communicating at 100 KHz in I 2 C mode, with 127 units addressable on a single I 2 C
communication line. However, in order to communicate via I 2 C you must first ensure that pull up resistors,
with a nominal value of 1K to 10K, are placed on the SCL and SDA communication lines coming from pins
two and three of the Data / Power Connector respectively. Data responses by the module are automatically
output via RS232, in case the host will be querying the module, it is necessary for the host to inform the
module that its responses are to be output via I
2 C. This can be done by sending command 254 /160 / 0 to
Matrix Orbital GLC24064 11