Dual MC33926 Motor Driver for Raspberry Pi [Assembled] (Pololu Robotics and Electronics)
Pololu Dual MC33926 Motor Driver for Raspberry Pi (Assembled) This add-on board enables a Raspberry Pi B+, A+, or Pi 2 to drive a pair of brushed DC motors. Its dual MC33926 motor drivers operate from 5 V to 28 V and can deliver a continuous 3 A (5 A peak) per motor. The default pin mappings make it easy to get started using our provided software, but the board also exposes most of the driver chips' I/O pins for more specialized applications. This version ships fully assembled with connectors soldered in. This motor driver board is an add-on for the Raspberry Pi Model B+, A+, or Pi 2 that lets it easily control a pair of bidirectional, brushed DC motors. The expansion board uses a pair of Freescale MC33926 motor drivers, which operate from 5 to 28 V and can deliver a continuous 3 A per channel (up to 5 A per channel for a few seconds). Other features include a reverse battery protection circuit and logic gates that reduce the number of I/O pins required to control the driver ICs effectively. The board ships fully populated with its SMD components; it is available either as a partial kit, with a female header and terminal blocks included but not soldered in, or fully assembled with these connectors soldered to the PCB. The board's default configuration uses six GPIO pins to control the motor drivers, making use of the Raspberry Pi's hardware PWM outputs, and it uses two additional pins to read status outputs from the drivers. However, the pin mappings can be customized if the defaults are not convenient, and other control inputs and outputs of the MC33926 ICs are accessible on the board for more advanced applications. Note that this motor driver add-on is designed specifically for newer versions of the Raspberry Pi with 40-pin GPIO headers, including the Model B+, Model A+, and Raspberry Pi 2 Model B. The board matches the Raspberry Pi HAT (Hardware Attached on Top) mechanical specification, although it does not conform to the full HAT specifications due to the lack of an ID EEPROM. (A footprint for adding your own EEPROM is available for applications where one would be useful; pull-ups on SDA, SCL, and WP are provided.) It is not practical to use this expansion board with the original Raspberry Pi Model A or Model B due to differences in their pinout and form factor. We also have a similar dual MC33926 shield for Arduinos and Arduino-compatible boards and basic single and dual MC33926 carriers for those using a different controller or with tighter space constraints. For a smaller, lower power, and lower cost alternative, consider the DRV8835 Dual Motor Driver for Raspberry Pi. Features - Wide operating voltage range: 5 V to 28 V - Output current: 3 A continuous (5 A peak) per motor - PWM operation up to 20 kHz, which is ultrasonic and allows for quieter motor operation - Motor indicator LEDs show what the outputs are doing even when no motor is connected - Board can optionally power the Raspberry Pi base directly through added regulator (not included) - Python library makes it easy to get started using this board as a motor driver expansion board - GPIO pin mappings can be customized if the default mappings are not convenient - Remaining motor driver pins are exposed for advanced use - Reverse-voltage protection on motor supply - Robust drivers: - Transient operation (< 500 ms) up to 40 V - Internal peak-current limiting gracefully reduces the output power if the current or temperature get too high - Under-voltage shutdown - Output short-to-ground and short-to-Vcc protection - Prototyping space for easier/cleaner construction of custom circuits Using the motor driver board This section explains how to use the dual MC33926 motor driver add-on board and provides some basic information about the motor driver pins to help get you started. However, we strongly encourage you to consult the MC33926 datasheet (1MB pdf) for detailed pin descriptions, truth tables, and electrical characteristics. This expansion board is essentially a breakout board for two MC33926 motor driver ICs with additional logic circuitry to simplify the motor control, so the datasheet is your best resource for answering questions not covered here. In the board's default state, the motor driver outputs and the Raspberry Pi are powered separately, though they share a common ground and the board's 3.3 V logic supply is provided by the Raspberry Pi. When used this way, the Raspberry Pi must be powered via its USB Micro-B receptacle, and the motor driver board must be supplied with 5 V to 28 V through its large VIN and GND pads. However, the motor driver board provides a set of three through-holes where you can conveniently connect an appropriate voltage regulator, allowing the motor supply to also power the Raspberry Pi (see the Powering the Raspberry Pi from the motor driver board section below). A reverse-voltage protection circuit helps prevent damage to the board in case the motor power supply is connected backward. The reverse-protected input voltage can be accessed for use in other circuits through the two pins labeled VOUT on the left side of the board. The board includes logic gates that enable drive/brake operation of the MC33926 drivers with only two control pins per motor (PWM and direction). As drive/brake operation usually provides a more linear relationship between PWM duty cycle and motor speed than drive/coast operation, we generally recommend using drive/brake operation when possible.