Switch and multiplex I2C signals with ease using TCA9543A and ATmega644
Simplify I2C connections
Published Sep 10, 2023
Click board™
I2C MUX 4 Click
Dev. board
EasyAVR v7
Compiler
NECTO Studio
MCU
ATmega644
Elevate your I2C communication capabilities and unlock the full potential of your connected devices with our I2C multiplexer solution
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Hardware Overview
How does it work?
I2C MUX 4 Click is based on the TCA9543A, a 2-channel, bidirectional translating I2C switch from Texas Instruments. The master SCL/SDA signal pair is directed to two channels of slave devices SC0/SD0 - SC1/SD1 where either individual channel or both channels can be selected determined by the programmable control register. The TCA9543A supports interrupt signals for the Master to detect an interrupt that can result from any of the slave devices connected to the interrupt pins on the output I2C channel header. It features I2C control using a single 8-bit control register in which bits 1 and 0 control the enabling and disabling of the two switch channels of I2C data flow, it supports a reset function, hot insertion, and has all switch channels deselected during Power-Up. This Click board™ includes a low dropout linear regulator
AP7331 from Diodes Incorporated to provide the 2.45V supply voltage for the TCA9543A. When the TCA9543APWR is turned on for the first time or anytime the device needs to be reset by cycling the power supply, which means that the Power-On reset requirements must be followed to ensure the I2C bus logic is initialized properly. The TCA9543APWR can also be reset to its default conditions by using the Power-On reset feature in the event of a glitch or data corruption. I2C MUX 4 Click communicates with MCU using the standard I2C 2-Wire interface that supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operation. The TCA9543A generates a programmable interrupt signal routed on the INT pin of the mikroBUS™ used for the Master to detect an interrupt which can result from any of the slave devices
connected to the output I2C channel pins. It also has two address pins that allow the choice of the least significant bit (LSB) of its I2C slave address which can be done by using the SMD jumper labeled as ADDR SEL, and a Reset function routed on the RST pin of the mikroBUS™ socket used to recover the TCA9543A from a bus-fault condition. 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
EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more
efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)
connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
64
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
4096
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 EasyAVR v7 as your development board.
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 I2C MUX 4 Click driver.
Key functions:
i2cmux4_get_ch_interrupt- Get channel interrupt functioni2cmux4_rmt_read_bytes- Generic read data functioni2cmux4_check_int- Check interrupt 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
* \brief I2cMux4 Click example
*
* # Description
* This example demonstrates the use of the I2C MUX 4 Click.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes the driver, enables the Click board and makes an initial log.
*
* ## Application Task
* In this example, we read the device ID register of the connected Click boards.
* Channel 0 : 6DOF IMU 12 Click [slave address: 0x68; reg: 0x00; id val.: 0x24],
* Channel 1 : Compass 3 Click [slave address: 0x30; reg: 0x2F; id val.: 0x0C].
* All data logs write on USB UART changes every 2 sec.
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "i2cmux4.h"
// ------------------------------------------------------------------ VARIABLES
static i2cmux4_t i2cmux4;
static log_t logger;
uint8_t rx_data;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
i2cmux4_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.
i2cmux4_cfg_setup( &cfg );
I2CMUX4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
i2cmux4_init( &i2cmux4, &cfg );
i2cmux4_power_on( &i2cmux4, I2CMUX4_ENABLE_POWER_ON );
Delay_ms ( 100 );
i2cmux4_set_channel( &i2cmux4, I2CMUX4_SEL_CH_ALL_DISABLE, 0x00 );
Delay_ms ( 100 );
}
void application_task ( void )
{
// CH 0 - 6DOF IMU 12 Click
i2cmux4_set_channel( &i2cmux4, I2CMUX4_SEL_CH_0, 0x68 );
Delay_ms ( 100 );
i2cmux4_rmt_read_bytes( &i2cmux4, 0x00, &rx_data, 1 );
Delay_ms ( 100 );
log_printf( &logger, " 6DOF IMU 12 Click \r\n" );
log_printf( &logger, "- - - - - - - - - - - - \r\n" );
log_printf( &logger, " ID = 0x%.2X \r\n", ( uint16_t ) rx_data );
log_printf( &logger, "----------------------- \r\n" );
Delay_ms ( 1000 );
// CH 1 - Compass 3 Click
i2cmux4_set_channel( &i2cmux4, I2CMUX4_SEL_CH_1, 0x30 );
Delay_ms ( 100 );
i2cmux4_rmt_read_bytes( &i2cmux4, 0x2F, &rx_data, 1 );
Delay_ms ( 100 );
log_printf( &logger, " Compass 3 Click \r\n" );
log_printf( &logger, "- - - - - - - - - - - - \r\n" );
log_printf( &logger, " ID = 0x%.2X \r\n ", ( uint16_t ) rx_data );
log_printf( &logger, "----------------------- \r\n" );
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
