Matrix Orbital GLK12232-25-SM - Manual (Page 13)

WARNINGS
• Do not apply and power with reversed polarization
• Do not apply any voltage other than the specified voltage
• Do not use any cables other than the cables supplied by Matrix
Orbital, unless aware of the modifications required
• Do not under any circumstances use an unmodified floppy drive
power cable in the wrong connector
2.2 Protocol Select Jumpers
The Protocol Select Jumpers, pictured below in Figure 12, provide the means necessary to toggle the
display module between RS-232, TTL and I 2 C protocols. As a default, the jumpers are set to RS-232 mode
with zero ohm resistors on the 232 jumpers. In order to place the display module in I 2 C mode you must first
remove the zero ohm resistors from the 232 jumpers and then solder the resistors on to the I2C jumpers, or
bridge solder across the pads. The display will now be in I
2 C 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 I
2 C jumpers and solder them to the TTL jumpers.
Figure 12: Protocol-Select-Jumpers
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