Matrix Orbital LK202-25 - Manual (Page 18)

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5.3 Communication
When communication of either text or commands is interrupted, try the steps below.
• First, check the communication cable for continuity. If you don't have an ohm meter, try using a
different communication cable. If you are using a PC try using a different Com/USB Port.
• Next, please ensure that the display module is set to communicate on the protocol that you are
using, by checking the Protocol Select Jumpers.
• In serial and USB protocols, ensure that the host system and display module are both
communicating on the same baud rate. The default rate for the display module is 19200 bps.
• Match Rx from your display to the transmitting pin from your host and the Tx pin to the
receiving pin.
• If you are communicating to the display via I²C
* please ensure that the data is being sent to the
correct address. The default slave address for the display module is 80.
• In I 2 C mode, connect Rx to the clock line of your controller and Tx to the data output.
• Unlock the display. See the Set and Save Data Lock command for more info.
• Finally, you may reset the display to its default settings using the Manual Override procedure
outlined below.
*Note: I²C communication will always require pull up resistors on SCL and SDA of one to ten kilohms.
5.4 Manual Override
Should the settings of your display become altered in a way that dramatically impacts usability, the
default settings can be temporarily restored. To override the display, please follow the steps below.
1. Disconnect power from your display.
2. Place a jumper on the middle two keypad pins, R5 and C1.
3. Reconnect power to your unit, and wait for the start screen before removing the jumper.
4. Settings will be temporarily
** overridden to the defaults listed in the Manual Override Settings
table. At this point any important settings, such as contrast, backlight, or baud rate, should not only
be set but saved so they remain when the override is removed.
Parameter Value
Backlight 255
Contrast 128
Baud Rate 19200
I
2
C Address 80
Table 11: Manual Override Settings
**Note: The display module will revert back to the old settings once turned off, unless desired settings are saved.