Matrix Orbital LK204-25 Legacy - Manual (Page 8)

 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