Optimize I2C communication and ensure smooth data exchange with LTC4306 and STM32F091RC
The ultimate I2C multiplexing solution
Published Feb 26, 2024
Click board™
I2C MUX 5 Click
Dev Board
Nucleo-64 with STM32F091RC MCU
Compiler
NECTO Studio
MCU
STM32F091RC
Elevate your project's efficiency by utilizing this solution to effortlessly switch between I2C devices, streamlining debugging, testing, and customization processes with ease
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Hardware Overview
How does it work?
I2C MUX 5 Click is based on the LTC4306, a 4-channel, 2-wire bus multiplexer with bus buffers to provide capacitive isolation between the upstream and downstream buses from Analog Devices. Multiplexing allows address expansion as well as addressing one of the multiple identical devices, thus resolving address conflict issues. Through software control, the LTC4306 splits the I2C bus into four sub-branches and connects the upstream 2-wire bus to any desired combination of downstream buses. It’s compatible with I2C and SMBus standards, has a programmable disconnect from stuck bus function, and provides four alert inputs for fault reporting with two GPIO pins configurable as inputs, open-drain, or push-pull outputs. I2C MUX 5 Click communicates with MCU using the standard I2C 2-Wire interface with a frequency up to 400kHz. It also has three address pins (A0, A1, and A2 that provide 27 specific addresses) programmed by the user
to determine the value of the last three LSBs of the slave address selected by onboard SMD jumpers labeled as ADDR SEL, allowing the selection of the slave address LSBs. In addition to I2C communication, this Click board™ has several additional features such as Interface Enable, Fault Alert, and Connection Ready functions. The Fault Alert pin, labeled as ALR and routed on the INT pin of the mikroBUS™ socket, is pulled low when a fault occurs to alert the MCU. This pin is pulled to a low logic level when any of the four alert input pins are low or when the 2-wire bus is stuck low and visually displays its function with a red LED marked as ALERT. The Enable pin, labeled as EN and routed on the CS pin of the mikroBUS™ socket, is used to turn on or off I2C communication to the LTC4306, and the Ready pin, labeled as RDY, routed on the AN pin of the mikroBUS™ socket, is used as connection ready output. This pin is pulled down when none
of the downstream channels is connected to the upstream bus and turns off when one or more downstream channels are connected to the upstream bus. The LTC4306 optionally provides two general-purpose input/output pins (GPIOs) that can be configured as logic inputs, open-drain outputs, or push-pull outputs. These pins are also connected to the two green LEDs, LD3 and LD2, which light up when the GP1 and GP2 pins, respectively, are low. 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
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
Start by selecting your development board and Click board™. Begin with the Nucleo-64 with STM32F091RC MCU as your development board.
Track your results in real time
Application Output
This Click board can be interfaced and monitored in two ways:
Application Output- Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.
UART Terminal- Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.
Software Support
Library Description
This library contains API for I2C MUX 5 Click driver.
Key functions:
i2cmux5_generic_write- I2C MUX 5 I2C writing functioni2cmux5_generic_read- I2C MUX 5 I2C reading functioni2cmux5_channel_read_byte- I2C MUX 5 I2C channel reading 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 I2cMux5 Click example
*
* # Description
* This app reads "Who am I" and "Status" register of the connected click boards
* to the I2C MUX 5 click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes I2C driver, set the default configuration and start to write log.
*
* ## Application Task
* This is an example that demonstrates the use of the I2C MUX 5 click board.
* In this example, we read "Who am I" ( or "Status" ) register
* of the connected click boards to the I2C MUX 5 click.
* Channel 1 : 6DOF IMU 9 click [slave address: 0x69; reg: 0x75; ID val.: 0xA9],
* Channel 2 : 6DOF IMU 11 click [slave address: 0x0E; reg: 0x00; ID val.: 0x2D],
* Channel 3 : RTC 10 click [slave address: 0x68; reg: 0x0F; St val.: 0x88],
* Channel 4 : Accel 10 click [slave address: 0x18; reg: 0x0F; ID val.: 0x44].
* Results are being sent to the Usart Terminal where you can track their changes.
*
* @author Nenad Filipovic
*
*/
#include "board.h"
#include "log.h"
#include "i2cmux5.h"
static i2cmux5_t i2cmux5;
static log_t logger;
static uint8_t rx_data;
void application_init ( void ) {
log_cfg_t log_cfg; /**< Logger config object. */
i2cmux5_cfg_t i2cmux5_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.
i2cmux5_cfg_setup( &i2cmux5_cfg );
I2CMUX5_MAP_MIKROBUS( i2cmux5_cfg, MIKROBUS_1 );
err_t init_flag = i2cmux5_init( &i2cmux5, &i2cmux5_cfg );
if ( init_flag == I2C_MASTER_ERROR ) {
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
i2cmux5_default_cfg ( &i2cmux5 );
log_info( &logger, " Application Task \r\n" );
Delay_ms ( 100 );
log_printf( &logger, "-------------------------------\r\n" );
log_printf( &logger, " I2C MUX 5 click \r\n" );
log_printf( &logger, "-------------------------------\r\n" );
}
void application_task ( void ) {
rx_data = i2cmux5_channel_read_byte( &i2cmux5, I2CMUX5_CH_1, I2CMUX5_SET_6DOF_IMU_9_ADDR, 0x75 );
Delay_ms ( 1000 );
log_printf( &logger, " CH-1 6DOF IMU 9 click : 0x%X \r\n", ( uint16_t )rx_data );
rx_data = i2cmux5_channel_read_byte( &i2cmux5, I2CMUX5_CH_2, I2CMUX5_SET_6DOF_IMU_11_ADDR, 0x00 );
Delay_ms ( 1000 );
log_printf( &logger, " CH-2 6DOF IMU 11 click : 0x%X \r\n", ( uint16_t )rx_data );
rx_data = i2cmux5_channel_read_byte( &i2cmux5, I2CMUX5_CH_3, I2CMUX5_SET_RTC_10_ADDR, 0x0F );
Delay_ms ( 1000 );
log_printf( &logger, " CH-3 RTC 10 click : 0x%X \r\n", ( uint16_t )rx_data );
rx_data = i2cmux5_channel_read_byte( &i2cmux5, I2CMUX5_CH_4, I2CMUX5_SET_ACCEL_10_ADDR, 0x0F );
Delay_ms ( 1000 );
log_printf( &logger, " CH-4 Accel 10 click : 0x%X \r\n", ( uint16_t )rx_data );
log_printf( &logger, "-------------------------------\r\n" );
i2cmux5_hw_reset( &i2cmux5 );
Delay_ms ( 1000 );
Delay_ms ( 1000 );
}
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
