Unlock a new level of precision in UART signal routing with SN74LV4052A and STM32L496AG
Breaking the barriers of serial routing: Redefine your UART connectivity experience!
Published Jul 22, 2025
Click board™
UART MUX Click
Dev. board
Discovery kit with STM32L496AG MCU
Compiler
NECTO Studio
MCU
STM32L496AG
With our UART line-switching solution, you can confidently address applications such as multi-device communication, data logging, and UART interface management, where precise and flexible routing is essential
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Hardware Overview
How does it work?
UART MUX Click is based on the SN74LV4052A, a dual 4-channel multiplexer and demultiplexer from Texas Instruments. Two control pins are used to switch to one of four available outputs, from a single UART input, from the mikroBUS™. Control pins labeled as A and B, are routed to the mikroBUS™ and can be operated by both 3.3V and 5V MCUs. The fourth control pin is labeled as EN pin, and it is used to enable the internal multiplexing switches of the IC, when is set to a HIGH logic level (it is active HIGH). A and B pins are routed to CS and PWM pins of the mikroBUS™ respectively. The active low Inhibit (INH) tri-state all the channels when high and when low, depending on the A and B inputs, one of the four independent input/outputs is connected to the
UART communication pins. INH pin is routed to the RST pin on the mikroBUS™. The ultra-low leakage current ensures that there is no signal interference from the inputs that are not selected by the A and B pins. A low crosstalk also ensures that the signal on one channel remains clean of interferences caused by other channels. This ensures a reliable operation of the IC and the Click board™ itself. The output signals can be connected via the 2x4 pin headers. Besides RX and TX pins, every output also has dedicated VCC and GND pins avalilable, so that user can easily route multple devices with this Click board™. 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 the limits. More information about the SN74LV4052A 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. 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.
Features overview
Development board
The 32L496GDISCOVERY Discovery kit serves as a comprehensive demonstration and development platform for the STM32L496AG microcontroller, featuring an Arm® Cortex®-M4 core. Designed for applications that demand a balance of high performance, advanced graphics, and ultra-low power consumption, this kit enables seamless prototyping for a wide range of embedded solutions. With its innovative energy-efficient
architecture, the STM32L496AG integrates extended RAM and the Chrom-ART Accelerator, enhancing graphics performance while maintaining low power consumption. This makes the kit particularly well-suited for applications involving audio processing, graphical user interfaces, and real-time data acquisition, where energy efficiency is a key requirement. For ease of development, the board includes an onboard ST-LINK/V2-1
debugger/programmer, providing a seamless out-of-the-box experience for loading, debugging, and testing applications without requiring additional hardware. The combination of low power features, enhanced memory capabilities, and built-in debugging tools makes the 32L496GDISCOVERY kit an ideal choice for prototyping advanced embedded systems with state-of-the-art energy efficiency.
Microcontroller Overview
MCU Card / MCU
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
STMicroelectronics
Pin count
169
RAM (Bytes)
327680
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the Discovery kit with STM32L496AG MCU as your development board.
Software Support
Library Description
This library contains API for UART MUX Click driver.
Key functions:
uartmux_send_command- Send commanduartmux_set_inhibit_communication- Set INT pinuartmux_choose_channel- Choose channel
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 UartMux Click example
*
* # Description
* This example reads and processes data from UART Mux Clicks.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes driver.
*
* ## Application Task
* Reads the received data.
*
* ## Additional Function
* - uartmux_process ( ) - The general process of collecting response
* from module.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "uartmux.h"
#include "string.h"
#define PROCESS_COUNTER 10
#define PROCESS_RX_BUFFER_SIZE 500
#define TEXT_TO_SEND "MikroE\r\n"
// ------------------------------------------------------------------ VARIABLES
#define DEMO_APP_RECEIVER
// #define DEMO_APP_TRANSMITER
static uartmux_t uartmux;
static log_t logger;
static uartmux_channel_t channel;
static int32_t rsp_size;
static char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
// ------------------------------------------------------- ADDITIONAL FUNCTIONS
static void uartmux_process ( void )
{
rsp_size = uartmux_generic_read( &uartmux, &uart_rx_buffer, PROCESS_RX_BUFFER_SIZE, &channel );
if ( rsp_size > 0 )
{
for ( int32_t cnt = 0; cnt < rsp_size; cnt++ )
{
log_printf( &logger, "%c", uart_rx_buffer[ cnt ] );
}
}
}
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
uartmux_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.
uartmux_cfg_setup( &cfg );
UARTMUX_MAP_MIKROBUS( cfg, MIKROBUS_1 );
uartmux_init( &uartmux, &cfg );
uartmux_set_inhibit_communication( &uartmux, UARTMUX_PIN_STATE_LOW );
}
void application_task ( void )
{
#ifdef DEMO_APP_RECEIVER
uartmux_process( );
#endif
#ifdef DEMO_APP_TRANSMITER
channel.state_a = UARTMUX_STATE_A_CHANNEL_1;
channel.state_b = UARTMUX_STATE_B_CHANNEL_1;
uartmux_generic_write( &uartmux, TEXT_TO_SEND, strlen( TEXT_TO_SEND ), &channel );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
#endif
}
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
Additional Support
Resources
Category:RS232
