Create reliable and accurate step motor driving solution with MTS62C19A and PIC18F4455

Dual full-bridge stepper motor driver with both full and half step control modes

Published Mar 26, 2024

Click board™

Stepper 7 Click

Dev. board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18F4455

Capable of driving both windings of a bipolar stepper motor or bidirectionally control two DC motors

Hardware Overview

How does it work?

Stepper 7 Click is based on the MTS62C19A, a dual full-bridge motor driver from Microchip. This IC's internal structure is symmetrical. It features two MOSFET H-bridges used to drive two coils of a bipolar step motor in both directions. The MTS62C19A uses a wide input voltage range - from 10V to 30V. This is the voltage used to energize the motor coils. A separate voltage level is used for the logic sections of this IC, and it is obtained from the mikroBUS™ +5V rail. The MTS62C19A has two PHASE inputs, which control the direction of current flow through H-bridges and, thus, the motor coils. The output current level is controlled by an internal PWM circuit, which is configured using two logic inputs (Ix0 and Ix1), a current sense resistor, and the voltage on the VREFx input - set to +5V on the Stepper 7 Click. By setting states on the Ix0 and Ix1 pins, the output current through the motor windings can be limited to 0%, 33%, 67%, and 100% of the maximum output current, which is set to about 500mA. This setup allows controlling the

step motor in both full-step and half-step modes by toggling states on the six control pins: PHASE1, PHASE2, I01, I02, I11, and I12. 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 connects an external voltage, ranging from 10V to 30V, 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, 40V is the absolute maximum voltage allowed as per the datasheet. Thus, the overtemperature protection might be activated when driving heavier loads. The recommended maximum voltage should not exceed 30V, as stated on the silk layer of the PCB. The MTS62C19A control lines are routed to the second IC on the Stepper 7 board, the MCP23S08, a well-known 8-bit I/O expander with a serial interface. It allows the control lines of the MTS62C19A IC to be driven via the SPI and the few pins it uses -

reducing the required pin count of the Stepper 7 click. This also allows for sending compact SPI messages instead of toggling several pins at once - which can introduce problems with timing sometimes, especially when those pins belong to different MCU ports. Changing the supply voltage for the port expander allows different SPI logic levels to be used for the communication - 3.3V or 5V, depending on the host MCU. This can be accomplished by switching the position of the onboard SMD jumper, labeled as PWR SEL. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL 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

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

2048

You complete me!

Accessories

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

Reset

RD0

RST

SPI Chip Select

RA3

SPI Clock

RB1

SCK

SPI Data OUT

RB2

MISO

SPI Data IN

RB3

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

Curiosity HPC Access MB 1 - upright/background hardware assembly

Necto DIP image step 7 hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

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 Stepper 7 Click driver.

Key functions:

stepper7_set_direction - This function sets the motor direction to clockwise or counter-clockwise in ctx->direction
stepper7_set_step_mode - This function sets the step mode resolution settings in ctx->step_mode
stepper7_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 7 Click example
 *
 * # Description
 * This example demonstrates the use of the Stepper 7 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 200 full steps and then counter-clockiwse for 200 half
 * steps and 800 1/8th steps with 2 seconds delay on driving mode change. All data is
 * being logged on the USB UART where you can track the program flow.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "stepper7.h"

static stepper7_t stepper7;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    stepper7_cfg_t stepper7_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.
    stepper7_cfg_setup( &stepper7_cfg );
    STEPPER7_MAP_MIKROBUS( stepper7_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == stepper7_init( &stepper7, &stepper7_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( STEPPER7_ERROR == stepper7_default_cfg ( &stepper7 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    log_printf ( &logger, " Move 200 full steps clockwise, speed: slow\r\n\n" );
    stepper7_set_direction ( &stepper7, STEPPER7_DIR_CW );
    stepper7_set_step_mode ( &stepper7, STEPPER7_MODE_FULL_STEP );
    stepper7_drive_motor ( &stepper7, 200, STEPPER7_SPEED_SLOW );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    log_printf ( &logger, " Move 200 half steps counter-clockwise, speed: medium\r\n\n" );
    stepper7_set_direction ( &stepper7, STEPPER7_DIR_CCW );
    stepper7_set_step_mode ( &stepper7, STEPPER7_MODE_HALF_STEP );
    stepper7_drive_motor ( &stepper7, 200, STEPPER7_SPEED_MEDIUM );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    log_printf ( &logger, " Move 800 1/8th steps counter-clockwise, speed: fast\r\n\n" );
    stepper7_set_direction ( &stepper7, STEPPER7_DIR_CCW );
    stepper7_set_step_mode ( &stepper7, STEPPER7_MODE_1_OVER_8_STEP );
    stepper7_drive_motor ( &stepper7, 800, STEPPER7_SPEED_FAST );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

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