Intermediate
30 min

Connect multiple input sources to a common output thanks to the ADG728 and STM32F031K6

Switch & stream: Analog multiplexer for seamless control

Analog MUX 2 Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

Analog MUX 2 Click

Dev Board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Enhance your data acquisition and signal processing systems with our analog multiplexer solution, enabling precise selection and routing of analog inputs to optimize data analysis

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Hardware Overview

How does it work?

Analog MUX 2 Click is based on the ADG728, a low voltage, CMOS 8-channel analog matrix switch with a serially controlled 2-wire interface from Analog Devices. The ADG728 can operate equally well as a multiplexer, demultiplexer, or switch array, providing more flexibility. It also features a low on-resistance closely matched between switches and is flat over the full signal range. During the Power-Up of the ADG728, all switching channels will be in the OFF condition, and the internal shift register will contain all zeros. All channels exhibit a ‘break-before-make’ switching action, preventing momentary shorting when switching channels. Each bit of the 8-bit serial word corresponds to one device switch. Internal switching channels are independently controlled by an individual bit, providing an option to activate

any, all, or none of the switches. All of the input channels of the multiplexer can be easily connected to a nine-pole spring action block terminal without having to use any additional tools, such as screwdrivers, while the output pin from the multiplexer is routed to the AN pin on the mikroBUS™ socket. Analog MUX 2 Click communicates with MCU using the standard I2C 2-Wire interface with a frequency of up to 400kHz. It also has two address pins (A0 and A1) programmed by the user to determine the value of the last two LSBs of the slave address, selected by onboard SMD jumpers labeled as ADDR SEL to an appropriate position marked as 0 and 1, allowing selection of the slave address LSBs. Also, this Click board™ has a Reset pin routed to the RST pin on the mikroBUS™ socket, which

clears the input register and turns all switches to the OFF condition. A new 8-bit word is written to the input shift register when changing the switch conditions. The ADG728 compares the state of switches from the previous write cycle to minimize glitches on its outputs. This can be achieved if the switch is already in the ON condition and is required to stay ON. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC 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.

Analog MUX 2 Click top side image
Analog MUX 2 Click bottom side image

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

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

32

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.

Click Shield for Nucleo-32 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Analog Output
PA0
AN
Reset
PA11
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB6
SCL
I2C Data
PB7
SDA
Power Supply
5V
5V
Ground
GND
GND
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Take a closer look

Schematic

Analog MUX 2 Click Schematic 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.

Click Shield for Nucleo-144 front image hardware assembly
Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly
Stepper 22 Click front image hardware assembly
Prog-cut hardware assembly
Stepper 22 Click complete accessories setup image hardware assembly
Nucleo-32 with STM32 MCU Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
STM32 M4 Clicker HA MCU/Select Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

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.

DEBUG_Application_Output

Software Support

Library Description

This library contains API for Analog MUX 2 Click driver.

Key functions:

  • analogmux2_set_channel - Analog MUX 2 set channel function

  • analogmux2_read_an_pin_value - Analog MUX 2 read AN pin value function

  • analogmux2_read_an_pin_voltage - Analog MUX 2 read AN pin voltage level function

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @file main.c
 * @brief AnalogMux2 Click example
 *
 * # Description
 * This application controls the multiplexing of a single input channel
 * with an eight-channel matrix switch.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes I2C and ADC driver, set Vref, STM32F407ZG - 2.048 V, PIC18F97J94 3.3 V, 
 * set the default configuration and start to write log.
 *
 * ## Application Task
 * This is an example that shows the use of a Analog MUX 2 click board.
 * In this example, we switch from channel AN0 to channel AN7, 
 * read and display the analog value and voltage on the active channel.
 * Results are being sent to the Usart Terminal where you can track their changes.
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "analogmux2.h"

static analogmux2_t analogmux2;
static log_t logger;

void application_init ( void ) {
    log_cfg_t log_cfg;                /**< Logger config object. */
    analogmux2_cfg_t analogmux2_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_printf( &logger, "\r\n" );
    log_info( &logger, " Application Init " );

    // Click initialization.

    analogmux2_cfg_setup( &analogmux2_cfg );
    ANALOGMUX2_MAP_MIKROBUS( analogmux2_cfg, MIKROBUS_1 );
    
    // Vref STM32F407ZG
    analogmux2_cfg.vref = 2.048;
    
    err_t init_flag = analogmux2_init( &analogmux2, &analogmux2_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    analogmux2_default_cfg ( &analogmux2 );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "-------------------------\r\n" );
    Delay_ms( 100 );
}

void application_task ( void ) {   
    for ( uint8_t ch_pos = ANALOGMUX2_SET_CHANNEL_0; ch_pos <= ANALOGMUX2_SET_CHANNEL_7; ch_pos++ ) {
        analogmux2_set_channel( &analogmux2, ch_pos );
        Delay_ms( 3000 );
        
        uint16_t analogmux2_an_value = 0;
    
        log_printf( &logger, "   CHANNEL    : AN%u     \r\n", ( uint16_t ) analogmux2_get_channel( &analogmux2 ) );
        log_printf( &logger, "- - - - - - - - - - - - - \r\n" );

        if ( analogmux2_read_an_pin_value ( &analogmux2, &analogmux2_an_value ) != ADC_ERROR ) {
            log_printf( &logger, "   ADC Value  : %u\r\n", analogmux2_an_value );
        }
    
        float analogmux2_an_voltage = 0;

        if ( analogmux2_read_an_pin_voltage ( &analogmux2, &analogmux2_an_voltage ) != ADC_ERROR ) {
            log_printf( &logger, "   AN Voltage : %.3f V \r\n", analogmux2_an_voltage );
        }
        
        log_printf( &logger, "-------------------------\r\n" );
    }   
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources

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