Matrix Orbital LK402-25 - Manual (Page 15)

15
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 R54, as illustrated below. This connection can be made using a zero ohm resistor,
recommended size 0603, or a solder bridge. The LK402-25 allows all voltage models to use the power
through DB-9 option, see the electrical specifications in Table 42 for voltage requirements.
Power Through DB9 Jumper
Protocol Select Jumpers
The Protocol Select Jumpers provide the means necessary to toggle the LK402-25 between RS-232, TTL
and I²C protocols. As a default, the jumpers are set to RS-232 mode with solder jumps on the 232
jumpers. In order to place the display module in I²C mode you must first remove the solder jumps from
the 232 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 0x50, unless it 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. Protocol tables are shown below where an `X` designates a connected jump while an ‘O’
signifies an open connection.
Table 8: RS232 Protocol Settings
RS232 TTL I
2
C
X X X 0 0 0 0
Table 9: TTL Protocol Settings
RS232 TTL I
2
C
O O O X X O O
Table 10: I 2 C Protocol Settings
RS232 TTL I
2
C
O O O O O X X