Matrix Orbital PK202-25 - Manual (Page 6)

1.3 Keypad Interface
The keypad interface takes row / column input and converts it to ASCII characters, which are delivered
out the RS-232 or I 2 C port to the associated controller. Note that the keypad is not used to directly control
any aspect of the operation of the display, which acts simply as a matrix to serial converter. To use the
keypad to control the display, the controller must be programmed accordingly.
1.4 Setup for Testing
Before setting up the application the user may want to try out the display. This is easily done with a PC.
If not equipped with a dual bay PC mounting kit, the following will be required;
• A 4-pin power connector of the type used to connect 3.5" floppy drive. Take care not to connect the
display to an unmodified spare power connector in a PC.
• A 5V power supply.
• A PC with a spare RS-232 port (COM1 or COM2).
• A 9 or 25 pin RS-232 serial cable. If using a 25 conductor cable, a 9 to 25 pin adapter will be required.
Figure 1: Connections for Testing
1. Refer to the Figure above for the following steps.
2. Wire the connector to the power supply. On most connectors the RED lead will go to +5V and the
BLACK lead to GND.
NOTE The Manufacturer’s Warranty becomes void if the unit is subjected to over-voltage
or reversed polarity.
3. Connect the display to the PC using the serial cable and adapter if required. Make sure the RS-232
cable includes the required ground lead. There must be no voltage differential between the RS-232
ground and the power supply ground.
Matrix Orbital PK202-25 2