Digilent DMC60C Manual de referencia - Página 13

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13 Quadrature Encoder Index

The DMC60C expansion port includes a pin (Encoder Index) for attaching a digital sensor or a

switch to automatically clear the quadrature encoder's position count. The onboard Microcontroller

uses an internal pull-up, which makes it possible to attach a switch directly without the need for an

external pull-up.

The DMC60C can be configured to clear the position count in response to a rising or falling (default)

edge on the Encoder Index pin. By default, this functionality is disabled, and any input applied to the

Encoder Index pin is ignored by the DMC60C.

The DMC60C may also be configured to clear the position count based on the logic level of a signal

applied to the Forward Limit or Reverse Limit pins of the expansion connector. By default, this

functionality is disabled. The active state required to clear the position count is dependent on the

configuration of the associated limit switch input. For example, if the Forward Limit switch is

configured as a normally open switch then a logic '0' on the Forward Limit pin will cause the position

count to be cleared when this functionality is enabled. If the Forward Limit switch is configured as a

normally closed switch, then a logic '1' on the Forward Limit pin causes the position count to be

cleared when this functionality enabled. Please note that the position count continues to be cleared

for as long as the associated pin remains driven to the active state.

The figures below show how to attach a switch to the Encoder Index pin of the expansion port.

Figure 13.1

Figure 13.2