ldc

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LDC click

LDC Click is a compact add-on board that measures inductance change which a conductive target causes when it moves into the inductor's AC magnetic field.

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Click library

• Author : Luka Filipovic
• Date : Jul 2021.
• Type : I2C type

Software Support

We provide a library for the LDC 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 LDC Click driver.

Standard key functions :

• ldc_cfg_setup Config Object Initialization function.

void ldc_cfg_setup ( ldc_cfg_t *cfg );

• ldc_init Initialization function.

err_t ldc_init ( ldc_t *ctx, ldc_cfg_t *cfg );

• ldc_default_cfg Click Default Configuration function.

err_t ldc_default_cfg ( ldc_t *ctx );

Example key functions :

• ldc_get_interrupt Get interrupt pin status.

uint8_t ldc_get_interrupt ( ldc_t *ctx );

• ldc_get_frequency Get frequency value calculated for specific channel.

err_t ldc_get_frequency ( ldc_t *ctx, uint8_t channel, uint16_t divider, float *frequency );

• ldc_calculate_inductance Calculate inductance relative to frequency.

float ldc_calculate_inductance ( float frequency );

Example Description

This example showcases abillity of the device to detect metal objects. It configures device for reading data from channel 0, checks if ID's are OK and reads data when interrupt is asserted and logs result.

The demo application is composed of two sections :

Application Init

Initialization of communication modules (I2C, UART) and additional pins. Then configures the device for reading data from channel 0, and checks if device ID's are correctly read, and read the currently set divider.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ldc_cfg_t ldc_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.
    ldc_cfg_setup( &ldc_cfg );
    LDC_MAP_MIKROBUS( ldc_cfg, MIKROBUS_1 );
    err_t init_flag = ldc_init( &ldc, &ldc_cfg );
    if ( I2C_MASTER_ERROR == init_flag ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    if ( ldc_default_cfg ( &ldc ) < 0 )
    {
        log_error( &logger, " Default configuration. " );
        for ( ; ; );
    }
    
    uint16_t temp_data = 0;
    ldc_generic_read( &ldc, LDC_REG_MANUFACTURER_ID, &temp_data );
    log_printf( &logger, "> Manufacturer ID: 0x%.4X\r\n", temp_data );
    if ( LDC_MANUFACTURER_ID != temp_data )
    {
        log_error( &logger, " Manufacturer ID. " );
        for ( ; ; );
    }
    
    ldc_generic_read( &ldc, LDC_REG_DEVICE_ID, &temp_data );
    log_printf( &logger, "> Device ID 0x%.4X\r\n", temp_data );
    if ( LDC_DEVICE_ID != temp_data )
    {
        log_error( &logger, " Device ID. " );
        for ( ; ; );
    }
    
    ldc_generic_read( &ldc, LDC_REG_CLOCK_DIVIDERS_CH0, &temp_data );
    divider = temp_data & 0x3FF;
    
    log_info( &logger, " Application Task " );
}

Application Task

Checks if interrupt pin is asserted, if so reads data from channel 0. Calculates and returns the frequency of the sensor. If the frequency is greater than 0, then it calculates the inductance of the sensor. It will log error and error values if it occurred.

void application_task ( void ) 
{
    if ( !ldc_get_interrupt( &ldc ) )
    {
        float frequency = 0.0;
        float inductance = 0.0;
        uint16_t status = 0;
        ldc_generic_read( &ldc, LDC_REG_STATUS, &status );
        if ( status & LDC_STATUS_DRDY )
        {
            err_t ret_val = ldc_get_frequency( &ldc, LDC_REG_DATA_CH0, divider, &frequency );
            if ( !ret_val )
            {
                log_printf( &logger, "> Freq[MHz]: %.3f\r\n", frequency );
                if ( frequency > 0 )
                {
                    inductance = ldc_calculate_inductance( frequency );
                }
                log_printf( &logger, "> L[uH]: %.3f\r\n", inductance );
                log_printf( &logger, "> ************************\r\n" );
                
                Delay_ms ( 500 );
            }
            else
            {
                log_error( &logger, " Reading data: %ld", ret_val );
            }
        }
    }
}

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.LDC

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.

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