Reduce voltage to a desirable level with ST1PS03 and PIC18F57Q43

Small in size, big in efficiency

Step Down 3 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

Step Down 3 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Regulate the output voltage to a precise level and provide a stable power supply for various applications

Hardware Overview

How does it work?

Step Down 3 Click is based on the ST1PS03, an ultra-low quiescent new generation buck converter from STMicroelectronics. The ST1PS03 targets a small quiescent current consumption and guarantees high-efficiency operation even down to a few microampere loads. It can provide up to 400mA output current with an output voltage from 1.6V to 3.3V on the VCC-OUT terminal, selectable using three digital control pins routed to the INT, PWM, and AN pins of the mikroBUS™ socket, and an input voltage ranging from 1.8V to 5.5V appliable on VCC-IN terminal. The ST1PS03 is based on a hysteretic comparator that senses the coil ripple current, held constant in all operation modes. The ST1PS03 changes the switching frequency depending on the input supply voltage to maintain a continuous ripple current on the selected coil. It seamlessly transitions between PFM (pulse frequency

modulation) and PWM (pulse width modulation) mode with low ripple and good load transient response. During PWM mode (heavy load), the device operates in continuous conduction up to 400mA and a switching frequency of 2MHz maximum. The device enters 100% duty cycle operation if the input voltage comes close to the selected output voltage. The regulator is turned OFF during this mode, and the output pin is directly connected to the input pin through the internal high-side MOSFET. Once the input voltage exceeds the 100% duty cycle, the device restarts to switch and regulates the output voltage again. This Click board™ also has a Power Good comparator which monitors the selected output voltage and provides information on the appropriate PGOOD terminal. Step Down 3 Click communicates with MCU using several GPIO pins. The AUX pin routed to the CS pin of the mikroBUS™

socket controls the auxiliary output terminal labeled as VCC-OUT-A. It provides the same regulated voltage level as VCC-IN-a input voltage, with less drop on the load switch circuitry when the AUX pin and EN pin, routed to the RST pin of the mikroBUS™ socket, are tied high. The VCC-OUT-A terminal allows connecting/disconnecting the other system load to the output of the ST1PS03. This Click board™ can only be operated with a 3.3V 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

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Used MCU Pins

mikroBUS™ mapper

Output Voltage Selection Pin 2

PA0

Device Enable

PA7

RST

Auxiliary

PD4

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

Output Voltage Selection Pin 1

PB0

PWM

Output Voltage Selection Pin 0

PA6

INT

SCL

SDA

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Charger 27 Click front image hardware assembly

PIC18F47Q10 Curiosity Nano front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Curiosity Nano with PICXXX Access MB 1 - upright/background hardware assembly

PIC18F57Q43 Curiosity MCU Step 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 Step Down 3 Click driver.

Key functions:

stepdown3_enable_device This function enables the auxiliary output (VOUT_AUX) by setting the AUX pin to HIGH logic state.
stepdown3_enable_aux_output This function disables the auxiliary output (VOUT_AUX) by setting the AUX pin to LOW logic state.
stepdown3_set_output_voltage This function sets the output voltage by setting the D2, D1, and D0 pins to a desired 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 Step Down 3 Click Example.
 *
 * # Description
 * This example demonstrates the use of Step Down 3 click board by
 * iterating through the entire output voltage range.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger, then enables the click board and disables
 * the auxiliary output.
 *
 * ## Application Task
 * Changes the output voltage every 3 seconds and displays the set voltage output value
 * on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "stepdown3.h"

static stepdown3_t stepdown3;   /**< Step Down 3 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    stepdown3_cfg_t stepdown3_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.
    stepdown3_cfg_setup( &stepdown3_cfg );
    STEPDOWN3_MAP_MIKROBUS( stepdown3_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == stepdown3_init( &stepdown3, &stepdown3_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    stepdown3_enable_device ( &stepdown3 );
    stepdown3_disable_aux_output ( &stepdown3 );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    static uint8_t vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    stepdown3_set_output_voltage ( &stepdown3, vout );
    switch ( vout )
    {
        case STEPDOWN3_OUT_VOLTAGE_1V6:
        {
            log_printf( &logger, " Output voltage: 1.6 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_1V8:
        {
            log_printf( &logger, " Output voltage: 1.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V1:
        {
            log_printf( &logger, " Output voltage: 2.1 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V5:
        {
            log_printf( &logger, " Output voltage: 2.5 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V7:
        {
            log_printf( &logger, " Output voltage: 2.7 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V8:
        {
            log_printf( &logger, " Output voltage: 2.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V0:
        {
            log_printf( &logger, " Output voltage: 3.0 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V3:
        {
            log_printf( &logger, " Output voltage: 3.3 V\r\n\n" );
            break;
        }
    }
    if ( ++vout > STEPDOWN3_OUT_VOLTAGE_3V3 )
    {
        vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    }
    Delay_ms ( 1000 );
    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;
}

// ------------------------------------------------------------------------ END

/*!
 * @file main.c
 * @brief Step Down 3 Click Example.
 *
 * # Description
 * This example demonstrates the use of Step Down 3 click board by
 * iterating through the entire output voltage range.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger, then enables the click board and disables
 * the auxiliary output.
 *
 * ## Application Task
 * Changes the output voltage every 3 seconds and displays the set voltage output value
 * on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "stepdown3.h"

static stepdown3_t stepdown3;   /**< Step Down 3 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    stepdown3_cfg_t stepdown3_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.
    stepdown3_cfg_setup( &stepdown3_cfg );
    STEPDOWN3_MAP_MIKROBUS( stepdown3_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == stepdown3_init( &stepdown3, &stepdown3_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    stepdown3_enable_device ( &stepdown3 );
    stepdown3_disable_aux_output ( &stepdown3 );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    static uint8_t vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    stepdown3_set_output_voltage ( &stepdown3, vout );
    switch ( vout )
    {
        case STEPDOWN3_OUT_VOLTAGE_1V6:
        {
            log_printf( &logger, " Output voltage: 1.6 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_1V8:
        {
            log_printf( &logger, " Output voltage: 1.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V1:
        {
            log_printf( &logger, " Output voltage: 2.1 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V5:
        {
            log_printf( &logger, " Output voltage: 2.5 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V7:
        {
            log_printf( &logger, " Output voltage: 2.7 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V8:
        {
            log_printf( &logger, " Output voltage: 2.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V0:
        {
            log_printf( &logger, " Output voltage: 3.0 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V3:
        {
            log_printf( &logger, " Output voltage: 3.3 V\r\n\n" );
            break;
        }
    }
    if ( ++vout > STEPDOWN3_OUT_VOLTAGE_3V3 )
    {
        vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    }
    Delay_ms ( 1000 );
    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;
}

// ------------------------------------------------------------------------ END

/*!
 * @file main.c
 * @brief Step Down 3 Click Example.
 *
 * # Description
 * This example demonstrates the use of Step Down 3 click board by
 * iterating through the entire output voltage range.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger, then enables the click board and disables
 * the auxiliary output.
 *
 * ## Application Task
 * Changes the output voltage every 3 seconds and displays the set voltage output value
 * on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "stepdown3.h"

static stepdown3_t stepdown3;   /**< Step Down 3 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    stepdown3_cfg_t stepdown3_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.
    stepdown3_cfg_setup( &stepdown3_cfg );
    STEPDOWN3_MAP_MIKROBUS( stepdown3_cfg, MIKROBUS_1 );
    if ( DIGITAL_OUT_UNSUPPORTED_PIN == stepdown3_init( &stepdown3, &stepdown3_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    stepdown3_enable_device ( &stepdown3 );
    stepdown3_disable_aux_output ( &stepdown3 );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    static uint8_t vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    stepdown3_set_output_voltage ( &stepdown3, vout );
    switch ( vout )
    {
        case STEPDOWN3_OUT_VOLTAGE_1V6:
        {
            log_printf( &logger, " Output voltage: 1.6 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_1V8:
        {
            log_printf( &logger, " Output voltage: 1.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V1:
        {
            log_printf( &logger, " Output voltage: 2.1 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V5:
        {
            log_printf( &logger, " Output voltage: 2.5 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V7:
        {
            log_printf( &logger, " Output voltage: 2.7 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_2V8:
        {
            log_printf( &logger, " Output voltage: 2.8 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V0:
        {
            log_printf( &logger, " Output voltage: 3.0 V\r\n\n" );
            break;
        }
        case STEPDOWN3_OUT_VOLTAGE_3V3:
        {
            log_printf( &logger, " Output voltage: 3.3 V\r\n\n" );
            break;
        }
    }
    if ( ++vout > STEPDOWN3_OUT_VOLTAGE_3V3 )
    {
        vout = STEPDOWN3_OUT_VOLTAGE_1V6;
    }
    Delay_ms ( 1000 );
    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;
}

// ------------------------------------------------------------------------ END