3 communication, 4 manual override – Matrix Orbital LK404-25 User Manual

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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 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 protocol, 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

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

C Address

Table 9: Manual Override Settings

**Note:

The display module will revert back to the old settings once turned off, unless desired settings are saved.