Multiplexing differential outputs has never been easier – choose between two corresponding outputs from a USB host or effortlessly merge outputs from two different hosts for enhanced versatility.
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Hardware Overview
How does it work?
USB MUX Click is based on the TS3USB30E, a USB 2.0 1:2 multiplexer/demultiplexer switch with a single enable from Texas Instruments. It is an ESD-protected device capable of bidirectional switching of high-speed USB 2.0 signals while offering little or no attenuation of the high-speed signals at the outputs. Besides the ESD protection, the TS3USB30E offers a low bit-to-bit skew and high channel-to-channel noise isolation. Also, besides USB 2.0, it is compatible with USB 1.1 standard. The maximum speed the TS3USB30E is
capable of is 480Mbps at USB 2.0. USB MUX Click communicates with the host MCU using a few GPIOs. The OE bus-switch enable pin allows users to isolate the bus when not in use and consume less current. With a LOW logic level set on the OE pin, you can use it in combination with the SEL pin to select one of two USB signal paths and connect it to a common USB signal path, with a LOW logic level to a USB1 and a HIGH logic level to a USB2. The USB1 is set by default over the pull-down resistors R5 and R6, which puts both OE and SEL
lines in a low logic state. In addition, the VBUS LED will indicate if the powered USB device is connected to the USB MUX Click. 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. 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
Nucleo-64 with STM32F091RC MCU offers a cost-effective and adaptable platform for developers to explore new ideas and prototype their designs. This board harnesses the versatility of the STM32 microcontroller, enabling users to select the optimal balance of performance and power consumption for their projects. It accommodates the STM32 microcontroller in the LQFP64 package and includes essential components such as a user LED, which doubles as an ARDUINO® signal, alongside user and reset push-buttons, and a 32.768kHz crystal oscillator for precise timing operations. Designed with expansion and flexibility in mind, the Nucleo-64 board features an ARDUINO® Uno V3 expansion connector and ST morpho extension pin
headers, granting complete access to the STM32's I/Os for comprehensive project integration. Power supply options are adaptable, supporting ST-LINK USB VBUS or external power sources, ensuring adaptability in various development environments. The board also has an on-board ST-LINK debugger/programmer with USB re-enumeration capability, simplifying the programming and debugging process. Moreover, the board is designed to simplify advanced development with its external SMPS for efficient Vcore logic supply, support for USB Device full speed or USB SNK/UFP full speed, and built-in cryptographic features, enhancing both the power efficiency and security of projects. Additional connectivity is
provided through dedicated connectors for external SMPS experimentation, a USB connector for the ST-LINK, and a MIPI® debug connector, expanding the possibilities for hardware interfacing and experimentation. Developers will find extensive support through comprehensive free software libraries and examples, courtesy of the STM32Cube MCU Package. This, combined with compatibility with a wide array of Integrated Development Environments (IDEs), including IAR Embedded Workbench®, MDK-ARM, and STM32CubeIDE, ensures a smooth and efficient development experience, allowing users to fully leverage the capabilities of the Nucleo-64 board in their projects.
Microcontroller Overview
MCU Card / MCU

Architecture
ARM Cortex-M0
MCU Memory (KB)
256
Silicon Vendor
STMicroelectronics
Pin count
64
RAM (Bytes)
32768
You complete me!
Accessories
Click Shield for Nucleo-64 comes equipped with two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the STM32 Nucleo-64 board with no effort. This way, Mikroe allows its users to add any functionality from our ever-growing range of Click boards™, such as WiFi, GSM, GPS, Bluetooth, ZigBee, environmental sensors, LEDs, speech recognition, motor control, movement sensors, and many more. More than 1537 Click boards™, which can be stacked and integrated, are at your disposal. The STM32 Nucleo-64 boards are based on the microcontrollers in 64-pin packages, a 32-bit MCU with an ARM Cortex M4 processor operating at 84MHz, 512Kb Flash, and 96KB SRAM, divided into two regions where the top section represents the ST-Link/V2 debugger and programmer while the bottom section of the board is an actual development board. These boards are controlled and powered conveniently through a USB connection to program and efficiently debug the Nucleo-64 board out of the box, with an additional USB cable connected to the USB mini port on the board. Most of the STM32 microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the STM32 Nucleo-64 board with our Click Shield for Nucleo-64, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic

Step by step
Project 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 USB MUX Click driver.
Key functions:
usbmux_set_oe_pin
- USB MUX set OE pin output function.usbmux_enable_output
- USB MUX enable output function.usbmux_set_output
- USB MUX select output function.
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 USB MUX Click Example.
*
* # Description
* This example demonstrates the use of the USB MUX Click board.
* This driver provides functions for device configurations
* and for the selection of the output.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization of the log UART, performing default configuration which disables the output.
*
* ## Application Task
* Reading user input from UART Terminal and using it for the selection of the output of
* disabling output of the USB MUX Click board.
*
* @author Stefan Ilic
*
*/
#include "board.h"
#include "log.h"
#include "usbmux.h"
static usbmux_t usbmux; /**< USB MUX Click driver object. */
static log_t logger; /**< Logger object. */
/**
* @brief Display possible selection function.
* @details This function is used to display possible selections for the user input.
* @return Nothing.
* @note None.
*/
static void display_selection ( void );
void application_init ( void )
{
log_cfg_t log_cfg; /**< Logger config object. */
usbmux_cfg_t usbmux_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.
usbmux_cfg_setup( &usbmux_cfg );
USBMUX_MAP_MIKROBUS( usbmux_cfg, MIKROBUS_1 );
if ( DIGITAL_OUT_UNSUPPORTED_PIN == usbmux_init( &usbmux, &usbmux_cfg ) )
{
log_error( &logger, " Communication init." );
for ( ; ; );
}
usbmux_default_cfg( &usbmux );
log_info( &logger, " Application Task " );
display_selection( );
}
void application_task ( void )
{
static char index;
if ( 1 == log_read( &logger, &index, 1 ) )
{
switch ( index )
{
case ( '0' ):
{
log_printf( &logger, " Turning output off. \r\n" );
usbmux_disable_output( &usbmux );
break;
}
case ( '1' ):
{
log_printf( &logger, " USB1 Enabled and selected. \r\n" );
usbmux_set_output( &usbmux, USBMUX_USB1_SELECT );
usbmux_enable_output( &usbmux );
break;
}
case ( '2' ):
{
log_printf( &logger, " USB2 Enabled and selected. \r\n" );
usbmux_set_output( &usbmux, USBMUX_USB2_SELECT );
usbmux_enable_output( &usbmux );
break;
}
default:
{
display_selection( );
}
}
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
static void display_selection ( void )
{
log_printf( &logger, " To select USB output settings \r\n" );
log_printf( &logger, " Send one of the numbers: \r\n" );
log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
log_printf( &logger, " '0' - Turn off output \r\n" );
log_printf( &logger, " '1' - Enable and select USB1 \r\n" );
log_printf( &logger, " '2' - Enable and select USB2 \r\n" );
log_printf( &logger, "---------------------------\r\n" );
}
// ------------------------------------------------------------------------ END