30 min

Experience the power of precise signal switching with MUX509 and STM32F429NI

Where pathways merge and opportunities multiply

MUX Click with Fusion for ARM v8

Published Aug 18, 2023

Click board™

MUX Click

Development board

Fusion for ARM v8


NECTO Studio



Step into a world of seamless signal routing with our CMOS analog multiplexing solution. Engineered for precision and flexibility, it empowers you to channel and manage various signals with efficiency and accuracy



Hardware Overview

How does it work?

MUX Click is based on the MUX509, a precise analog multiplexing IC from Texas Instruments. The MUX509 can be used with a wide range of power supplies. It can handle dual and single power supplies and symmetrical and non-symmetrical ones. This allows it to be used in a wide range of different applications. Another property of the MUX509 is that it has dual inputs and dual output. Three control pins switch one of four input pairs to a single output pair. Control pins labeled A0 and A1 are routed to the mikroBUS™ and can be operated by both 3.3V and 5V MCUs. The third control pin, labeled as EN pin, is used to enable the output when set to a HIGH logic level (active HIGH). A0 and A1 pins are routed to the RST and PWM pins of the mikroBUS™, respectively, while the EN pin is routed to the CS pin on the mikroBUS™. The MUX509 IC is targeted toward working with differential signals rather than single-ended inputs. Each input comprises two pins: SNA, and SNB, where N represents the channel number from 1 to 4. When a specific

channel is selected (N), the SNA and SNB pins will be routed to the DA and DB output pins. Each signal pair is equipped with a 100nF parallel capacitor and 100Ω series resistance for improved stability. The input and the output signal pins are routed to the standard 2.54mm pitch 2x5 pins header on the Click board™. The ultra-low leakage current ensures no signal interference from the inputs not selected by the A0 and A1 pins. Low crosstalk also ensures that the signal on one channel remains clean of interferences caused by other channels. The break-before-make switching action prevents any two inputs from being switched simultaneously at the output. This ensures the reliable operation of the IC and the Click board™ itself. MUX click does not use the power from the mikroBUS™ power rails, except for the LED indicator. Instead, a three-pole screw terminal connects an external power supply. Considering the minimum input voltage of 10V or ±5V, a power supply should be connected to this terminal before operating the Click board™.

Depending on the type of the used power supply (single supply or symmetrical/dual supply), it should be connected to the power supply input terminal, accordingly: GND is the reference ground connection, VSS is the negative voltage connection terminal (GND if a single power supply is used), and VDD is the positive voltage connection terminal. The input and output signals can be connected via the 2x5 pins header. As mentioned, the MUX509 IC supports rail-to-rail operation, supporting input and output signals ranging from VSS (or GND) up to VDD. Independent power supply input allows the user to work with a wide range of signal amplitudes, depending on the application requirements, as long as the power supply stays within limits. More information about the MUX509 can be found in the attached datasheet. However, the Click board™ comes equipped with a library that contains easy-to-use functions and a usage example that may be used as a reference for the development.

MUX Click hardware overview image

Features overview

Development board

Fusion for ARM v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different ARM® Cortex®-M based MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, Fusion for ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the Fusion for ARM v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for ARM v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Fusion for ARM v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

MUX Control 0
Chip Enable
MUX Control 1
Power supply

Take a closer look


MUX Click Schematic schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for ARM v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN 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 Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for MUX Click driver.

Key functions:

  • mux_active_mux_channel - Select active MUX channel

  • mux_device_disable - Disable MUX device function

  • mux_device_enable - Enable MUX device 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 
 * \brief MUX Click example
 * # Description
 * Sets the current active channel. Changes the channel every 5 sec.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initializes GPIO module and sets RST, CS and PWM pins as OUTPUT.
 * ## Application Task  
 * Changes currently active channel every 5 sec.
 * \author Luka Filipovic
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "mux.h"

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

static mux_t mux;
static log_t logger;

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

void application_init ( void )
    log_cfg_t log_cfg;
    mux_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.

    mux_cfg_setup( &cfg );
    mux_init( &mux, &cfg );
    Delay_ms( 100 );
    log_printf( &logger, "        MUX Click\r\n" );
    log_printf( &logger, "------------------------\r\n" );
    mux_device_enable( &mux );
    log_printf( &logger, "    Enable MUX device\r\n" );
    log_printf( &logger, "------------------------\r\n" );
    Delay_ms( 100 );

void application_task ( void )
    uint16_t n_cnt;
    for ( n_cnt = MUX_CHANNEL_1A_AND_1B; n_cnt < MUX_CHANNEL_END; n_cnt++ )
        log_printf( &logger, "      CHANNEL  S%u\r\n", n_cnt );
        log_printf( &logger, "------------------------\r\n" );
        mux_active_mux_channel( &mux, n_cnt );
        Delay_ms( 5000 );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support