Control stepper motors with A4988 and STM32F091RC
Microstepping driver for controlling bipolar stepper motors with a built-in translator for easy operation
Published Mar 05, 2024
Click board™
Stepper 2 Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Achieve bidirectional movement of the stepper motors with just two signals, one for controlling the rotation direction and the other for controlling the steps
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Hardware Overview
How does it work?
Stepper 2 Click is based on the A4988, a DMOS micro-stepping driver from Allegro Microsystems. Additional features of the Stepper click include under-voltage, shoot-through, short circuit, overcurrent, and thermal protection so that the Click board™ can operate reliably. Its input voltage range of up to 35V can drive a wide range of stepper motors. This highly integrated IC offers a very 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 and its decay throughout the rotation cycle, a constant torque is achieved for every position. The current regulator uses an internal comparator, DA converter (DAC), and external sensing resistor. The sensing resistor limits the current to about 1.6A (for a reference voltage of 3.3V). The Click board™ is equipped
with the input and output screw terminals. The right terminal connects the external power supply, which should stay within the range from 8V to 35V. The stepper motor can be connected via screw terminals, with their input terminals labeled 1A, 1B, and 2A, 2B. Stepper 2 Click uses the GPIO pins to allow the host MCU to control the motor. A LOW to HIGH transition on the ST 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 three pins: MS1, M2, and MS3. It is possible to work with five-movement step sizes, ranging from full step size up to sixteenth step size. MS1, MS2, and MS3 pins are routed to the SMD jumpers labeled as STEP MODE (J1, J2, and J3), allowing step size to be selected by moving each of them according to the micro-stepping resolution truth table. This device supports the sleep mode, activated by a LOW logic level on the sleep SL pin.
This will power down the unused sections of the A4988 IC, reducing power consumption to a minimum. After the wake-up event (logic HIGH on the SL pin), at least 1ms of delay is required until the charge pump capacitors are recharged, allowing normal operation of the output stage drivers. The EN pin allows the host MCU to turn ON or OFF the output stage MOSFETs of the A4988 IC. Asserting this pin to a LOW logic level enables the output stage. The RST pin sets DACs and the phase current polarity to the initial Home state. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. 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 2 Click driver.
Key functions:
stepper2_drive_motor- This function drives the motor for the specific number of steps at the selected speedstepper2_set_direction- This function sets the motor direction by setting the DIR pin logic statestepper2_enable_device- This function enables the device by setting the ENABLE pin to low logic state
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 2 Click Example.
*
* # Description
* This example demonstrates the use of the Stepper 2 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 steps and then counter-clockiwse for 32 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 compatible stepper motor for this click board:
* https://www.mikroe.com/step-motor-5v
*
* @author Stefan Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "stepper2.h"
static stepper2_t stepper2; /**< Stepper 2 Click driver object. */
static log_t logger; /**< Logger object. */
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
stepper2_cfg_t stepper2_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.
stepper2_cfg_setup( &stepper2_cfg );
STEPPER2_MAP_MIKROBUS( stepper2_cfg, MIKROBUS_1 );
if ( DIGITAL_OUT_UNSUPPORTED_PIN == stepper2_init( &stepper2, &stepper2_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
stepper2_default_cfg ( &stepper2 );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
log_printf ( &logger, " Move 64 steps clockwise\r\n\n" );
stepper2_set_direction ( &stepper2, STEPPER2_DIR_CW );
stepper2_drive_motor ( &stepper2, 64, STEPPER2_SPEED_VERY_FAST );
Delay_ms ( 2000 );
log_printf ( &logger, " Move 32 steps counter-clockwise\r\n\n" );
stepper2_set_direction ( &stepper2, STEPPER2_DIR_CCW );
stepper2_drive_motor ( &stepper2, 32, STEPPER2_SPEED_FAST );
Delay_ms ( 2000 );
}
int main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
return 0;
}
// ------------------------------------------------------------------------ END
