Matrix Orbital LK404-25 - Manual (Page 12)

8
Power Through DB9 Jumper
In order to provide power through pin 9 of the DB-9 Connector you must connect the Power Through
DB-9 Jumper labelled D, as illustrated below. This connection can be made using a zero ohm resistor,
recommended size 0603, or a solder bridge. The LK404-25 allows all voltage models to use the power
through DB-9 option, see the Voltage Specifications for power requirements.
Figure 8: Power Through DB9 Jumper
Protocol Select Jumpers
The Protocol Select Jumpers provide the means necessary to toggle the LK404-25 between RS-232, TTL
and I²C protocols. As a default, the jumpers are set to RS-232 mode with solder jumps on the RS232
jumpers. In order to place the display module in I²C mode you must first remove the solder jumps from
the RS232 jumpers and then place them on the I
2 C jumpers. The display will now be in I²C mode and
have a default slave address of 80, unless changed with the appropriate command. Similarly, in order to
change the display to TTL mode, simply remove the zero ohm resistors from the RS232 or I²C jumpers
and solder them to the TTL jumpers.