Manual

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Revision: October 31, 2011
Note: This document applies to REV A of the board.
1300 NE Henley Court, Suite 3
Pullman, WA 99163
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Doc: 502-117 page 1 of 2
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Overview
The PmodENC Rotary Encoder Module
features a rotary shaft encoder with integral
push-button that provides rotate-right, rotate-
left, and button-press outputs. The module also
includes a sliding switch that provides an on/off
output.
Features include:
• a rotary push-button shaft encoder
• a slide switch with a series resistor
• a 6-pin header
• small form factor (1.5” x 0.75”).
Functional Description
There are four outputs on the PmodENC
module, labeled A, B, BTN, and SWT. Outputs
A and B are the encoded outputs from the
rotary shaft encoder. In principle, the rotary
shaft encoder behaves like a cam connected to
a central shaft. Rotating the shaft operates two
push-button switches, as shown in Figure 2.
Depending on which way the shaft is rotated,
one of the switches closes before the other.
Likewise, as the rotation continues, one switch
opens before the other. When the shaft is
stationary (the detent position) both switches
are open (logic 1).
5 = GND
1 = A
2 = B
3 = BTN
4 = SWT
6 = VCC
Figure 1 PmodENC Pin Signals
Figure 2 Rotary Shaft Encoder Circuitry