Achieve enhanced motor control and efficiency with DRV8871 and STM32F091RC
Dominate with swift motor drive
Published Feb 26, 2024
Click board™
DC Motor 9 Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Monitor the current consumption of your motor at all times. Upgrade your engineering toolkit, and embrace the possibilities of brushed motor control.
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Hardware Overview
How does it work?
DC Motor 9 Click is based on the DR8871, a brushed DC motor driver with internal current sensing, by Texas Instruments. This IC is an integrated H-Bridge driver with a current regulation circuit limiting the current through the connected load with a single resistor. Unlike many other solutions, no external sensing resistors are required. A low ON resistance through the H-Bridge reduces the overall power dissipation, while an advanced control circuit injects dead-time intervals whenever the outputs change their state, preventing current shoot-throughs. The DRV8871 integrates protection features, including undervoltage, overcurrent, and overtemperature protection. Each of these events will cause the H-Bridge MOSFETs to be disabled. After removing a fault condition, the device will continue its operation. Two methods can be used to control the motor: the first consists of applying a constant logic level to IN1 and IN2 inputs. While one of the inputs is held at a HIGH logic level, the other should be held at a LOW logic level. The direction of the motor rotation depends on which input is at the
HIGH logic level. The second method involves holding one pin to the LOW level while applying a PWM signal to the other. Changing the PWM frequency makes it possible to control the speed of the motor, while the direction of the motor rotation is determined by the pin the PWM signal is applied to. Both pins to HIGH will set all the MOSFETs in HIGH-Z mode (coast), allowing the backEMF-generated current to return to the source through the MOSFET body diodes. If both IN1 and IN2 pins are set to the LOW logic level, the connected motor is in a braking state. When the PWM signal is applied, the motor will be switched between the braking and rotating modes, causing it to slow down, depending on the pulse width of the applied PWM signal. The frequency of the PWM signal can range between 0 and 200 kHz, with the limitation that the PWM pulses must stay above 800ns for proper detection. Current through the connected load is internally limited to a maximum of 3.6A. A higher current will cause the overcurrent protection to be activated. The peak current through the motor is
limited to about 3.2A, ensuring reliable spin-up while preventing the overcurrent protection from being activated, even if a large load torque is applied. Although there is a low resistance across the H-Bridge, the current should be monitored to prevent excessive heating in situations where the load is reasonably high. Therefore, an additional IC is added, allowing the current to be monitored. The Click board™ uses the LT1999, a bidirectional current sense amplifier from Analog Devices (Linear Technology division). It is used to amplify voltage drop across the shunt resistor so that it can be accurately sampled. The output of the LT1999 IC is routed to the AN pin of the mikroBUS™, allowing the host MCU to sense the current using its integrated ADC module. This Click board™ can only be operated with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing 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.
DC Gear Motor - 430RPM (3-6V) represents an all-in-one combination of a motor and gearbox, where the addition of gear leads to a reduction of motor speed while increasing the torque output. This gear motor has a spur gearbox, making it a highly reliable solution for applications with lower torque and speed requirements. The most critical parameters for gear motors are speed, torque, and efficiency, which are, in this case, 520RPM with no load and 430RPM at maximum efficiency, alongside a current of 60mA and a torque of 50g.cm. Rated for a 3-6V operational voltage range and clockwise/counterclockwise rotation direction, this motor represents an excellent solution for many functions initially performed by brushed DC motors in robotics, medical equipment, electric door locks, and much more.
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
1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.
2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.
3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.
Software Support
Library Description
This library contains API for DC Motor 9 Click driver.
Key functions:
dcmotor9_generic_read- This function read ADC data.dcmotor9_pwm_start- This function starts PWM module.dcmotor9_set_duty_cycle- This function sets the PWM duty cycle.
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 DC Motor 9 Click Example
*
* # Description
* DC Motor 9 Click is a brushed DC motor driver with the current limiting and
* current sensing. It can be operated by two logic signals, allowing to drive
* the connected motor in two different ways:
* it can use fixed logic levels for the direction control,
* or it can be controlled by a PWM signal, offering an additional speed control
* option.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes GPIO, PWM and logger and enables the click board.
*
* ## Application Task
* This is a example which demonstrates the use of DC Motor 9 Click board.
* DC Motor 9 Click controls DC Motor speed via PWM interface.
* It shows moving in the both directions from slow to fast speed
* and from fast to slow speed.
* Results are being sent to the Usart Terminal where you can track their changes.
*
* @author Nikola Peric
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "dcmotor9.h"
// ------------------------------------------------------------------ VARIABLES
static dcmotor9_t dcmotor9;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
dcmotor9_cfg_t dcmotor9_cfg;
/**
* 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.
dcmotor9_cfg_setup( &dcmotor9_cfg );
DCMOTOR9_MAP_MIKROBUS( dcmotor9_cfg, MIKROBUS_1 );
if ( dcmotor9_init( &dcmotor9, &dcmotor9_cfg ) == PWM_ERROR )
{
log_info( &logger, "---- Application Init Error ----" );
log_info( &logger, "---- Please, run program again ----" );
for ( ; ; );
}
dcmotor9_set_duty_cycle ( &dcmotor9, DCMOTOR9_PWM_DUTY_PERCENT_0 );
dcmotor9_enable( &dcmotor9 );
dcmotor9_pwm_start( &dcmotor9 );
log_info( &logger, "---- Application Task ----" );
Delay_ms( 1000 );
}
void application_task ( void )
{
static float duty;
static uint8_t n_cnt;
dcmotor9_clockwise ( &dcmotor9 );
log_printf( &logger, "> CLOCKWISE <\r\n" );
dcmotor9_enable ( &dcmotor9 );
for ( n_cnt = 10; n_cnt > 0; n_cnt-- )
{
duty = ( float ) n_cnt ;
duty /= 10;
dcmotor9_set_duty_cycle( &dcmotor9, duty );
Delay_ms( 500 );
}
for ( n_cnt = 1; n_cnt <= 10; n_cnt++ )
{
duty = ( float ) n_cnt ;
duty /= 10;
dcmotor9_set_duty_cycle( &dcmotor9, duty );
Delay_ms( 500 );
}
log_printf( &logger, "* Pull break *\r\n" );
dcmotor9_short_brake( &dcmotor9 );
Delay_ms( 1000 );
dcmotor9_counter_clockwise ( &dcmotor9 );
log_printf( &logger, "> COUNTER CLOCKWISE <\r\n" );
for ( n_cnt = 1; n_cnt <= 10; n_cnt++ )
{
duty = ( float ) n_cnt ;
duty /= 10;
dcmotor9_set_duty_cycle( &dcmotor9, duty );
Delay_ms( 500 );
}
for ( n_cnt = 10; n_cnt > 0; n_cnt-- )
{
duty = ( float ) n_cnt ;
duty /= 10;
dcmotor9_set_duty_cycle( &dcmotor9, duty );
Delay_ms( 500 );
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END
