1five volt modules, Figure 2-3, N 2.1.1.1) – Matrix Orbital LK204-25 Legacy User Manual
Page 8: Pc wiring display module wiring

Do not apply more than +5Vdc to pin #9 on the DB-9 connector.
Connector pinout is as follows:
1 2 3 4
Figure 2-3 Power connector
Pin 1
+5.0 VDC (+7 to +15 VDC with wide voltage option)
Pin 2
SCL (I
2
C clock)
Pin 3
SDA (I
2
C data)
Pin 4
Ground
2.1.1.1Five Volt Modules
If the LK204-25 is used in a PC it is tempting to plug a spare power connector into the unit. Don't do this!
Wiring for the PC power connector and that required for the LK204-25 are different as shown in Figure 2-4
below.
PC wiring
Display module wiring
+5 V
+5 V
GND
GND
+12 V
Figure 2-4 Power Connector wiring differences
If you don't want to modify cable wiring yourself, Matrix Orbital can supply an adapter cable designed to
use with the LK204-25 when it's installed in a PC. The cable is wired as shown in Figure 2-5 below. Note
that this cable does not provide connections for I
2
C.
Figure 2-5 Five volt Power Cable
LK204-25 rev 1
8