The Stepper 14 Click is a Click board™ that features the DRV8847PWPR, a step motor driver, from Texas Instruments. This Click board™ provides a bipolar step motor controle, It features an H-bridge bipolar step motor driver, which supports full-, half-, quarter-, or eighth-step modes. This Click board™ also carries a port expander so that the communication can be done with a minimal number of pins, through the mikroBUS™ I2C bus. This Click board™ offers thermal protection, integrated kickback voltage protection, it has a wide range of input voltage, protection against current shoot-through the H-Bridge and high current capability. These features make Stepper 14 Click an ideal solution for driving motors in any application that demands a precise and safe step motor driver.
Stepper 14 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.
This Click board™ is equipped with two integrated circuits. The step motor driver IC is the DRV8847PWPR, a dual full-bridge motor driver from Texas Instruments. This IC internal structure is somewhat symmetrical. It features two MOSFET H-bridges used to drive two coils of a bipolar step motor in both directions. The DRV8847PWPR uses a wide input voltage range - from 2.7V to 18V. This is the voltage used to energize the motor coils. A jumper (JP4) is used to select whether to use external power supply or to obtain the power supply from the mikroBUS™ +3.3V or +5V rail. The DRV8847PWPR has two PHASE inputs which are used to control the direction of current flow through H-bridges and thus, the motor coils. It also allows controlling step motor in both full step and half step modes, by toggling states on MS1 and MS1 pins.
The bipolar step motor coils can be connected to the onboard screw terminals. There are two terminals, used to connect each of the step motor coils. The third connector is used to connect an external voltage, ranging from 2.7V to 18V, depending on the used motor voltage requirements. It should be noted that without a valid external voltage connected to this terminal, the motor will not work. Also, it should be noted that 20V is an absolute maximum voltage allowed as per datasheet, thus the overtemperature protection might be activated when driving heavier loads. The recommended maximum voltage should not exceed 18V, as stated on the silkscreen layer of the PCB.
All of the DRV8847PWPR control lines are routed to the second IC on Stepper 14 board, which is the PCA9538A, a well-known 8bit I/O expander with a serial interface, used on many of the MikroElektronika’s designs for its simplicity and reliability. It allows the control lines of the DRV8847PWPR IC to be driven via the I2C and few pins it uses - reducing the required pin count of the Stepper 14 Click. This also allows for sending compact I2C messages, instead of toggling several pins at once - which can introduce problems with timing sometimes, especially when those pins belong to different MCU ports. By changing states of the six control pins, it is possible to drive the step motor in full step mode as well as the half step mode. However, provided MikroElektronika libraries contain simple and intuitive functions to fully control the bipolar step motor, connected to Stepper 14 Click. Their usage is demonstrated in the included example application, which can be used as a reference for a custom design.
The motor power supply can be connected to the input terminal labeled as VIN and should be within the range of 2.7V to 18V. Stepper motor coils can be connected to the terminals labeled as A1, B2, B1, and A2. The Click board™ supports an optional external power supply for the motor in order to work.
However, this Click board™ can be supplied and interfaced with both 3.3V and 5V without the need for any external components. The onboard SMD jumper labeled as VCC SEL allows voltage selection for interfacing with both 3.3V and 5V microcontrollers.
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