Digilent 410-195P - Manual

P P m m o o d d K K Y Y P P D D ™ ™ R R e e f f e e r r e e n n c c e e M M a a n n u u a a l l
Revision: October 6, 2011
Note: This document applies to REV B of the board.
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Overview
The PmodKYPD is an array of buttons used for
input.
Features include:
• 16 labelled keys (0-F)
•
12-pin header
Functional Description
The PmodKYPD uses a standard 12-pin Pmod
header that indicates which row and which
column has been pressed in the array of
buttons.
Connector J1 – Column/Row Indicators
Pin
Signal Description
1 COL4 Column 4
2 COL3 Column 3
3 COL2 Column 2
4 COL1 Column 1
5 GND Power Supply Ground
6 VCC Power Supply (3.3V)
7 ROW4 Row 4
8 ROW3 Row 3
9 ROW2 Row 2
10 ROW1 Row 1
11 GND Power Supply Ground
12 VCC Power Supply (3.3V)
Device Usage
The PmodKYPD is set up as a matrix in which
each row of buttons from left to right are tied to
a row pin, and each column from top to bottom
is tied to a column pin. This gives the user four
row pins and four column pins to address the
button push.
To read a button’s state, the column pin in
which the button resides must be pulled low.
This enables all of the buttons in that column.
When a button in that column is pushed, the
corresponding row pin will read logic low.
All of the buttons can be read by walking a
logic 0 through each column pin (keeping the
other pins at logic high) and reading the row
pins. This will read the state of each button.