2.3
Keypad Interface Connector
The GLK12232-25-SM provides a
Keypad Interface Connector
which allows for up to a five by five
matrix style keypad to be directly connected to the display module. Key presses are generated, when a short
is detected between a row and a column. When a key press is generated a character, which is associated
with the particular key press, is automatically sent on the Tx communication line. If the display module is
running in I
2
C mode, the "Auto Transmit Keypress" function may be turned off, to allow the key presses to
remain in the buffer so that they may be polled. The character that is associated with each key press may also
be altered using the "Assign Key Codes" command, for more detailed information see the Keypad Section.
Figure 13: Keypad Interface Connector
2.4
GPO
A unique feature of the GLK12232-25-SM is the ability to control relays and other external devices
using a
General Purpose Output
(3), which can provide up to 20 mA of current and +5Vdc from the positive
side of the GPO. This is limited by a 240 ohm resistor which is located directly above the positive pin as
pictured below in Figure 14 on the following page. If the device, which is being driven by a GPO, requires a
Matrix Orbital
GLK12232-25-SM
9
