Make controlling a bipolar stepper motor easier and more efficient with A3967 and STM32F091RC
Ideal solution for small stepping motors in office automation, as well as commercial and industrial equipment
Published Mar 05, 2024
Click board™
STEPPER Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Control the bipolar stepper motor's movement in both directions using simple step control inputs from your host MCU
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Hardware Overview
How does it work?
Stepper Click is based on the A3967, a micro-stepping driver with a translator from Allegro Microsystems. This highly integrated IC offers a simple bipolar stepper motor control interface, thanks to the integrated translator section. This section controls the output drivers, providing smooth action of the stepper motor. By controlling the current intensity throughout the rotation cycle, a constant torque is achieved for every position. The current regulator uses an internal comparator, DA converter, and external sensing resistor. The sensing resistor value determines the maximum current during the operation, limiting it to 568mA when using 5V or 350mA when using 3.3V as the reference voltage. Additional features of the Stepper Click include under-voltage, shoot-through, and thermal protection so the Click board™ can operate reliably. Its input voltage range of up to 25V can drive a wide range of stepper motors with
up to 750mA max. The Click board™ offers a choice to use a power source for driving the motor: one is the external voltage routed to the input connector, while the other is a 5V power rail from the mikroBUS™. While using the external connector, the voltage of the external power supply should remain below 25V. Selection between the external power supply and 5V rail from the mikroBUS™ can be made by moving the jumper labeled as MOTOR PWR to either the 5V position or EXT position. The stepper motor can be connected via the disconnectable crimp style XH connector with 2.5mm pitch, usually found on many small-size stepper motors. This header is optional and comes unsoldered in case some other type of header or connector needs to be used instead. Stepper Click uses GPIO pins to communicate with the host MCU. A LOW to HIGH transition on the STP pin will perform one rotational step. The logic
state on the DIR pin controls the direction of the rotation. The step size is determined by two pins: MS1 and MS2. It is possible to work with full steps (using two phases), half, quarter, and eighth steps. The SMD jumper labeled as the EN pin can be used to route the #EN pin of the IC to the EN pin of the mikroBUS™. This allows the host MCU to turn the A3967 ON or OFF. By default, this jumper is positioned to route the #EN pin to the GND directly, permanently enabling the IC. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the I/O LEVEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.
Features overview
Development board
Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M0
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
32768
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
The 28BYJ-48 is an adaptable 5VDC stepper motor with a compact design, ideal for various applications. It features four phases, a speed variation ratio of 1/64, and a stride angle of 5.625°/64 steps, allowing precise control. The motor operates at a frequency of 100Hz and has a DC resistance of 50Ω ±7% at 25°C. It boasts an idle in-traction frequency greater than 600Hz and an idle out-traction frequency exceeding 1000Hz, ensuring reliability in different scenarios. With a self-positioning torque and in-traction torque both exceeding 34.3mN.m at 120Hz, the 28BYJ-48 offers robust performance. Its friction torque ranges from 600 to 1200 gf.cm, while the pull-in torque is 300 gf.cm. This motor makes a reliable and efficient choice for your stepper motor needs.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F091RC MCU as your development board.
Track your results in real time
Application Output via Debug Mode
1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.
2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.
Software Support
Library Description
This library contains API for STEPPER Click driver.
Key functions:
stepper_set_step_mode- This function sets the step mode resolution settingsstepper_set_direction- This function sets the motor direction by setting the DIR pin logic statestepper_drive_motor- This function drives the motor for the specific number of steps at the selected speed
Open Source
Code example
The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.
/*!
* @file main.c
* @brief Stepper Click Example.
*
* # Description
* This example demonstrates the use of the Stepper click board by driving the
* motor in both directions for a desired number of steps.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver and performs the click default configuration.
*
* ## Application Task
* Drives the motor clockwise for 64 full steps and then counter-clockiwse for 128 half
* steps with 2 seconds delay before changing the direction. All data is being logged on
* the USB UART where you can track the program flow.
*
* @note
* Step Motor 5v [MIKROE-1530] is a fully compatible stepper motor for this click board:
* https://www.mikroe.com/step-motor-5v
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "stepper.h"
static stepper_t stepper; /**< Stepper Click driver object. */
static log_t logger; /**< Logger object. */
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
stepper_cfg_t stepper_cfg; /**< Click config object. */
/**
* Logger initialization.
* Default baud rate: 115200
* Default log level: LOG_LEVEL_DEBUG
* @note If USB_UART_RX and USB_UART_TX
* are defined as HAL_PIN_NC, you will
* need to define them manually for log to work.
* See @b LOG_MAP_USB_UART macro definition for detailed explanation.
*/
LOG_MAP_USB_UART( log_cfg );
log_init( &logger, &log_cfg );
log_info( &logger, " Application Init " );
// Click initialization.
stepper_cfg_setup( &stepper_cfg );
STEPPER_MAP_MIKROBUS( stepper_cfg, MIKROBUS_1 );
if ( DIGITAL_OUT_UNSUPPORTED_PIN == stepper_init( &stepper, &stepper_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
stepper_default_cfg ( &stepper );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
log_printf ( &logger, " Move 64 full steps clockwise \r\n\n" );
stepper_set_step_mode ( &stepper, STEPPER_MODE_FULL_STEP );
stepper_set_direction ( &stepper, STEPPER_DIR_CW );
stepper_drive_motor ( &stepper, 64, STEPPER_SPEED_FAST );
Delay_ms ( 2000 );
log_printf ( &logger, " Move 128 half steps counter-clockwise \r\n\n" );
stepper_set_step_mode ( &stepper, STEPPER_MODE_HALF_STEP );
stepper_set_direction ( &stepper, STEPPER_DIR_CCW );
stepper_drive_motor ( &stepper, 128, STEPPER_SPEED_VERY_FAST );
Delay_ms ( 2000 );
}
int main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
