Datasheet

1300 Henley Court

Pullman, WA 99163

509.334.6306

www.digilentinc.com

PmodHB3™ Reference Manual

Revised January 20, 2016

This manual applies to the PmodHB3 rev. E

DOC#: 502-069

Other product and company names mentioned may be trademarks of their respective owners.

Page 1 of 4

Overview

The Digilent PmodHB3 offers a 2A H-Bridge circuit with external feedback to drive small to medium sized DC

motors.

1 Functional Description

The PmodHB3 utilizes a full H-Bridge circuit to allow users to drive DC motors from the system board. Two external

pins are provided on the Pmod for sensor feedback on the DC motor, if desired.

2 Interfacing with the Pmod

The PmodHB3 communicates with the host board via the GPIO protocol. Like all H-Bridges, care must be taken to

avoid causing a potential short within the circuitry. In terms of this Pmod, this means that the Direction pin must

not change state while the Enable pin is at a high voltage state. If this does occur, one set of switches that are

driving the motor will be closing while the other set is opening, allowing for the possibility for both sets of switches

to be open at the same time, creating a short.

To drive the motor at a specific speed, users will need to choose a static direction (forwards or backwards

corresponding to high or low voltage) on the Direction pin, and then perform pulse-width modulation on the

The PmodHB3.

 2A H-bridge circuit

 Drive a DC motor with operation voltage up

to 12V

 Screw terminal blocks for connection to the

motor

 Separate header for external motor

feedback

 Small PCB size for flexible designs 1.2 in ×

0.8 in (3.0 cm × 2.0 cm)

 6-pin Pmod connector with GPIO interface

 Follows Digilent Pmod Interface

Specification Type 5

 Example code available in resource center

Features include:

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300 Henley Court Pullman, WA 99163 509.334.6306 www.digilentinc.com PmodHB3™ Reference Manual Revised January 20, 2016 This manual applies to the PmodHB3 rev. E Overview The Digilent PmodHB3 offers a 2A H-Bridge circuit with external feedback to drive small to medium sized DC motors. Features include:        The PmodHB3.
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PmodHB3™ Reference Manual Enable pin. The more often that an enable pin is driven high within a set time frame, the faster the DC motor will spin. 10% VCC 10% Duty Cycle 3.3V * 10% = 0.33V 90 % Figure 1 Gnd 2KHz 3.3V * 50% = 1.75V Figure 2 50% Duty Cycle 2KHz 3.3V * 75% = 2.48V Figure 3 75% Duty Cycle 2KHz Table 1. Frequency and corresponding rotation. The way that this works is that when voltage is being applied, the motor is driven by the changing magnetic forces.
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PmodHB3™ Reference Manual 3 Physical Dimensions The pins on the pin header are spaced 100 mil apart. The PCB is 1.2 inches long on the sides parallel to the pins on the pin header and 0.8 inches long on the sides perpendicular to the pin header. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.