Simplify complex wiring configurations with MCP23017 and STM32F031K6

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Expand 2 Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

Expand 2 Click

Dev. board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Expand, connect, conquer - with our game-changing general-purpose I/O expander

Hardware Overview

How does it work?

Expand 2 Click is based on the MCP23017, a 16-bit general purpose parallel I/O expansion for I2C bus from Microchip. The MCP23017 consists of multiple 8-bit configuration registers for input, output, and polarity selection. The host MCU can enable the I/Os as either inputs or outputs by writing the I/O configuration bits with data for each input or output kept in the corresponding input or output register. This port expander represents a simple solution when additional I/Os are needed while keeping interconnections to a minimum. This Click board™ communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 1.7MHz. The MCP23017 has a

7-bit I2C address with the first four MSBs fixed to 0100. The address pins A0, A1, and A2 are programmed by the user and determine the value of the last three LSBs of the slave address, which can be selected by positioning onboard SMD jumpers labeled as ADDR SEL to an appropriate position marked as 1 or 0. This way, the MCP23017 provides the opportunity of the 64 possible different I2C addresses by positioning the SMD jumper to an appropriate position. Besides, it also features an interrupt feature, routed to the INT pin of the mikroBUS™ socket, indicating to the host controller that an input state has been changed. Two interrupt pins on the MCP23017 can be

associated with their respective ports or logically OR’ed together so that both pins will activate if either port causes an interrupt. The desired interrupt can be selected by positioning an onboard SMD jumper labeled INT SEL to an appropriate position. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, it is allowed for both 3.3V and 5V capable MCUs to use the communication lines properly. However, the 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 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The

board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,

and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.

Nucleo 32 with STM32F031K6 MCU double side image

Microcontroller Overview

MCU Card / MCU

Architecture

ARM Cortex-M0

MCU Memory (KB)

Silicon Vendor

STMicroelectronics

Pin count

RAM (Bytes)

4096

You complete me!

Accessories

Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.

Used MCU Pins

mikroBUS™ mapper

Reset

PA11

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

Interrupt

PA12

INT

I2C Clock

PB6

SCL

I2C Data

PB7

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Click Shield for Nucleo-144 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.

Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly

Stepper 22 Click front image hardware assembly

Stepper 22 Click complete accessories setup image hardware assembly

Nucleo-32 with STM32 MCU Access MB 1 - upright/background hardware assembly

STM32 M4 Clicker HA MCU/Select 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 Expand 2 Click driver.

Key functions:

expand2_set_bit_port_a - Function set bit to 8-bit register address from PORTA of MCP23017 chip
expand2_toggle_bit_port_a - Function toggle bit from 8-bit register address from PORTA of MCP23017 chip
expand2_clear_bit_port_a - Function clear bit from 8-bit register address from PORTA of MCP23017 chip

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 
 * \brief Expand2 Click example
 * 
 * # Description
 * This application demonstrates the use of the Expand 2 click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes the driver and logger, and then sets the click 
 * default configuration: PORTA as output, PORTB as input with pull-ups on all pins.
 * 
 * ## Application Task  
 * Sets other pin of PORTA every 3 seconds, then reads and displays the status of 
 * both ports on USB UART.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "expand2.h"

// ------------------------------------------------------------------ VARIABLES

static expand2_t expand2;
static log_t logger;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    expand2_cfg_t 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.

    expand2_cfg_setup( &cfg );
    EXPAND2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    expand2_init( &expand2, &cfg );

    expand2_default_cfg ( &expand2 );

    log_printf( &logger, "----------------\r\n" );
    log_printf( &logger, " Expand 2 Click \r\n" );
    log_printf( &logger, "----------------\r\n" );

    Delay_ms( 100 );
}

void application_task ( void )
{
    //  Task implementation.

    uint8_t port_status;
    uint8_t pin_position;

    for ( pin_position = 0; pin_position < 8; pin_position++ )
    {
        expand2_set_port_a( &expand2, EXPAND2_I2C_MODULE_ADDRESS_0, pin_position );
        
        port_status = expand2_read_port_a( &expand2, EXPAND2_I2C_MODULE_ADDRESS_0 );

        log_printf( &logger, " Status PA (output): %d\r\n", (uint16_t) port_status );
        
        port_status = expand2_read_port_b( &expand2, EXPAND2_I2C_MODULE_ADDRESS_0 );

        log_printf( &logger, " Status PB (input) : %d  \r\n", (uint16_t) port_status );
        log_printf( &logger, "----------------\r\n" );
        
        Delay_ms( 3000 );
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


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