Compass 7 Click

Compass 7 Click is a compact add-on board perfect for applications like an electronic compass. This board features the MMC5633NJL, a monolithic complete 3-axis AMR magnetic sensor with on-chip signal processing and an integrated digital bus from MEMSIC. It can measure magnetic fields within the full-scale range of ±30 Gauss (G) with up to 0.0625mG per LSB resolution at 20bits operation mode and 2mG total RMS noise level, enabling heading accuracy of ±1º in electronic compass applications. Also, an integrated SET/RESET function eliminates thermal variation-induced offset error (Null field output) and clears the residual magnetization resulting from powerful external fields.

Click Product page

Click library

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

Software Support

We provide a library for the Compass 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 Compass 7 Click driver.

Standard key functions :

• compass7_cfg_setup Config Object Initialization function.

  void compass7_cfg_setup ( compass7_cfg_t *cfg );

• compass7_init Initialization function.

  err_t compass7_init ( compass7_t *ctx, compass7_cfg_t *cfg );

• compass7_default_cfg Click Default Configuration function.

  err_t compass7_default_cfg ( compass7_t *ctx );

Example key functions :

• compass7_set_measurement_mode This function sets the control and ODR registers for the selected measurement mode.

  err_t compass7_set_measurement_mode ( compass7_t *ctx, uint8_t mode );

• compass7_get_magnetic_flux This function reads the raw values of X, Y, and Z axis and converts them to magnetic flux data in Gauss.

  err_t compass7_get_magnetic_flux ( compass7_t *ctx, compass7_magnetic_flux_t *flux );

• compass7_get_temperature This function reads the temperature measurements in Celsius.

  err_t compass7_get_temperature ( compass7_t *ctx, float *temperature );

Example Description

This example demonstrates the use of Compass 7 Click board by reading and displaying the magnetic field strength of 3-axis as well as the temperature measurements in Celsius.

The demo application is composed of two sections :

Application Init

Initializes the driver and performs the Click default configuration.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    compass7_cfg_t compass7_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.
    compass7_cfg_setup( &compass7_cfg );
    COMPASS7_MAP_MIKROBUS( compass7_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == compass7_init( &compass7, &compass7_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    if ( COMPASS7_ERROR == compass7_default_cfg ( &compass7 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

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

Application Task

Starts the single magnetic measurement and reads the magnetic field strength of 3-axis in Gauss, then starts the temperature measurement and reads the temperature in Celsius. The results are being displayed on the USB UART every 100ms approximately.

void application_task ( void )
{
    compass7_magnetic_flux_t magnetic_flux;
    float temperature;
    if ( ( COMPASS7_OK == compass7_set_measurement_mode ( &compass7, COMPASS7_MEAS_SINGLE_M ) ) &&
         ( COMPASS7_OK == compass7_get_magnetic_flux ( &compass7, &magnetic_flux ) ) )
    {
        log_printf ( &logger, " X: %.2f G\r\n", magnetic_flux.x_axis );
        log_printf ( &logger, " Y: %.2f G\r\n", magnetic_flux.y_axis );
        log_printf ( &logger, " Z: %.2f G\r\n", magnetic_flux.z_axis );
    }
    if ( ( COMPASS7_OK == compass7_set_measurement_mode ( &compass7, COMPASS7_MEAS_SINGLE_T ) ) &&
         ( COMPASS7_OK == compass7_get_temperature ( &compass7, &temperature ) ) )
    {
        log_printf ( &logger, " Temperature: %.2f C\r\n\n", temperature );
    }
    Delay_ms ( 100 );
}

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.Compass7

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.