I2C MUX 7 click

I2C MUX 7 Click is a compact add-on board representing a bidirectional selector dedicated to applications with I2C slave address conflicts. This board features the PI4MSD5V9547, an octal bidirectional translating multiplexer controlled by the I2C-bus from Texas Instruments. Only one SCL/SDA channel can be selected at a time, determined by the contents of the programmable control register. The board powers up with Channel 0 connected, allowing immediate communication between the Master and downstream devices on that channel.

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Click library

• Author : Stefan Filipovic
• Date : Jan 2022.
• Type : I2C type

Software Support

We provide a library for the I2C MUX 7 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for I2C MUX 7 Click driver.

Standard key functions :

• i2cmux7_cfg_setup Config Object Initialization function.

  void i2cmux7_cfg_setup ( i2cmux7_cfg_t *cfg );

• i2cmux7_init Initialization function.

  err_t i2cmux7_init ( i2cmux7_t *ctx, i2cmux7_cfg_t *cfg );

• i2cmux7_default_cfg Click Default Configuration function.

  err_t i2cmux7_default_cfg ( i2cmux7_t *ctx );

Example key functions :

• i2cmux7_set_channel This function sets the desired channel active and configures its slave address.

  err_t i2cmux7_set_channel ( i2cmux7_t *ctx, uint8_t ch_sel, uint8_t ch_slave_addr );

• i2cmux7_read_channel This function reads the currently selected channel value.

  err_t i2cmux7_read_channel ( i2cmux7_t *ctx, uint8_t *ch_sel );

• i2cmux7_generic_read This function reads a desired number of data bytes starting from the selected register by using I2C serial interface.

  err_t i2cmux7_generic_read ( i2cmux7_t *ctx, uint8_t reg, uint8_t *rx_buf, uint8_t rx_len );

Example Description

This example demonstrates the use of I2C MUX 7 click board by reading the device ID of a 6DOF IMU 11 and Compass 3 click boards connected to the channels 0 and 7 respectfully.

The demo application is composed of two sections :

Application Init

Initializes the driver and resets the device.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    i2cmux7_cfg_t i2cmux7_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.
    i2cmux7_cfg_setup( &i2cmux7_cfg );
    I2CMUX7_MAP_MIKROBUS( i2cmux7_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == i2cmux7_init( &i2cmux7, &i2cmux7_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    i2cmux7_reset_device ( &i2cmux7 );

    log_info( &logger, " Application Task " );
}

Application Task

Reads the device ID of the connected click boards. Channel 0 : 6DOF IMU 11 click [slave address: 0x0E; reg: 0x00; id: 0x2D], Channel 7 : Compass 3 click [slave address: 0x30; reg: 0x2F; id: 0x0C]. All data is being logged on the USB UART where you can check the device ID.

void application_task ( void )
{
    uint8_t channel, device_id;
    if ( I2CMUX7_OK == i2cmux7_set_channel ( &i2cmux7, DEVICE0_POSITION, DEVICE0_SLAVE_ADDRESS ) )
    {
        if ( I2CMUX7_OK == i2cmux7_read_channel ( &i2cmux7, &channel ) )
        {
            log_printf( &logger, " --- Channel %u --- \r\n", ( uint16_t ) ( channel & I2CMUX7_CHANNEL_NUM_MASK ) );
        }
        if ( I2CMUX7_OK == i2cmux7_generic_read ( &i2cmux7, DEVICE0_REG_ID, &device_id, 1 ) )
        {
            log_printf( &logger, " %s - Device ID: 0x%.2X \r\n\n", ( char * ) DEVICE0_NAME, ( uint16_t ) device_id );
        }
        Delay_ms ( 1000 );
    }
    if ( I2CMUX7_OK == i2cmux7_set_channel ( &i2cmux7, DEVICE1_POSITION, DEVICE1_SLAVE_ADDRESS ) )
    {
        if ( I2CMUX7_OK == i2cmux7_read_channel ( &i2cmux7, &channel ) )
        {
            log_printf( &logger, " --- Channel %u --- \r\n", ( uint16_t ) ( channel & I2CMUX7_CHANNEL_NUM_MASK ) );
        }
        if ( I2CMUX7_OK == i2cmux7_generic_read ( &i2cmux7, DEVICE1_REG_ID, &device_id, 1 ) )
        {
            log_printf( &logger, " %s - Device ID: 0x%.2X \r\n\n", ( char * ) DEVICE1_NAME, ( uint16_t ) device_id );
        }
        Delay_ms ( 1000 );
    }
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.I2CMUX7

Additional notes and informations

Depending on the development board you are using, you may need USB UART click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.