34 lines
2.3 KiB
Markdown
34 lines
2.3 KiB
Markdown
# Stepper_A3967
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This is a derived class of **StepperControl** designed to operate stepper motors driven by an [Allegro A3967](https://cdn.sparkfun.com/datasheets/Robotics/A3967-Datasheet.pdf) (or equivalent) chip.
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The Allegro A3967 is a specialized driver designed for stepper motors. It contains a built-in PWM generator and pre-programmed stepping modes. Wiring for the [Sparkfun EasyDriver Stepper Motor Board](https://learn.sparkfun.com/tutorials/easy-driver-hook-up-guide?_ga=2.152816825.1841726212.1688220137-156607829.1686369274) that uses this chip is as follows:
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#### **Power Connections**
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* *GND* - connect to GND on the ESP32, and to ground of external DC power supply
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* *M+* - connect to external DC power supply that will drive stepper motor. An on-board regulator also uses this supply to provide VCC to the rest of the board. For use with an ESP32, you must short the 3.3V/5V jumper with a blob of solder to select 3.3V
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#### **Motor Connections**
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* *Motor A* - connect to the "A" coil of the stepper motor
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* *Motor B* - connect to the "B" coil of the stepper motor
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#### **Control Connections**
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* *MS1, MS2* - connect to two digital pins on the ESP32 - used to set the step type mode
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* *STEP, DIR* - connect to two digital pins on the ESP32 - used to step the motor and set the direction
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* *ENABLE* - connect to a digital pin on the ESP32 - used to enable/disable to motor driver
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* *SLEEP, RESET* - already pulled high on the EasyDriver board, so no connection neeed. If using a different driver board, ensure these pins are pulled high, else connect to VCC
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* *PFD* - not used
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The **Stepper_A3967** class includes the following constructor:
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* `Stepper_A3967(int MS1, int MS2, int STEP, int DIR, int ENABLE)`
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* controls the driver board using 5 digital pins from the ESP32, where the parameters specify the pin numbers. Supports the following step type modes:
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* FULL_STEP_TWO_PHASE
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* HALF_STEP
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* QUARTER_STEP
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* EIGHTH_STEP
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❗Note: The A3967 chip does not support a short brake state. Calls to the `brake()` method, as well as setting the *endAction* parameter in the `move()` and `moveTo()` methods to **StepperControl::BRAKE** have no effect on the motor driver.
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---
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[↩️](../Stepper.md) Back to the Stepper Motor Control page
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