Matrix Orbital VK204-25 Legacy - Manual (Page 19)

2.7 Keypad Interface Connector
The VK204-25 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, on
page 35.
Figure 21: Keypad Interface Connector
3 Troubleshooting
3.1 The display does not turn on when power is applied.
• First, you will want to make sure that you are using the correct power connector. Standard floppy drive
power cables from your PC power supply may fit on the Power/Data Connector however they do not
have the correct pin out as can be seen in figure 11 on page 7. Matrix Orbital supplies power cable
adapters for connecting to a PC, which can be found in the Accessories Section on page 2.
• The next step is to check the power cable which you are using for continuity. If you don’t have an
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