DIGI POT 9 Click

DIGI POT 9 Click is a compact add-on board used as a digitally controlled potentiometer. This board features the AD5235, a dual-channel, nonvolatile memory, digitally controlled potentiometer from Analog Devices. The AD5235's versatile programming via an SPI-compatible serial interface allows multiple modes of operation and adjustment. The resistor wiper position is determined by the RDAC register contents, which act as a scratchpad register, allowing unlimited changes of resistance settings. The nominal resistance of the RDAC between terminal A and terminal B (RAB) is 250 kΩ with 1024 positions (10-bit resolution).

Click Product page

Click library

• Author : Stefan Filipovic
• Date : Jun 2021.
• Type : SPI type

Software Support

We provide a library for the DIGIPOT9 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 DIGIPOT9 Click driver.

Standard key functions :

• digipot9_cfg_setup Config Object Initialization function.

  void digipot9_cfg_setup ( digipot9_cfg_t *cfg );

• digipot9_init Initialization function.

  DIGIPOT9_RETVAL digipot9_init ( digipot9_t *ctx, digipot9_cfg_t *cfg );

• digipot9_default_cfg Click Default Configuration function.

  void digipot9_default_cfg ( digipot9_t *ctx );

Example key functions :

• digipot9_generic_write This function writes two data bytes to the selected command and address by using SPI serial interface.

  err_t digipot9_generic_write ( digipot9_t *ctx, uint8_t command, uint8_t address, uint16_t data_in );

• digipot9_generic_read This function reads two data bytes from the selected command and address by using SPI serial interface.

  err_t digipot9_generic_read ( digipot9_t *ctx, uint8_t command, uint8_t address, uint16_t *data_out );

• digipot9_set_wiper_1 This function sets wiper 1 to desired value.

  err_t digipot9_set_wiper_1 ( digipot9_t *ctx, uint16_t data_in );

Example Description

This example demonstrates the use of DIGI POT 9 Click board.

The demo application is composed of two sections :

Application Init

Initializes the driver and makes an initial log.

void application_init ( void )
{
    log_cfg_t log_cfg;            /**< Logger config object. */
    digipot9_cfg_t digipot9_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.

    digipot9_cfg_setup( &digipot9_cfg );
    DIGIPOT9_MAP_MIKROBUS( digipot9_cfg, MIKROBUS_1 );
    err_t init_flag  = digipot9_init( &digipot9, &digipot9_cfg );
    if ( SPI_MASTER_ERROR == init_flag ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    digipot9_default_cfg ( &digipot9 );
    log_info( &logger, " Application Task " );
}

Application Task

Iterates through the entire wiper range and sets both wipers to the iterator value once per second. The current wiper position will be displayed on the USB UART.

void application_task ( void )
{
    for ( uint16_t cnt = DIGIPOT9_WIPER_ZERO_SCALE; cnt <= DIGIPOT9_WIPER_FULL_SCALE; cnt += 50 )
    {
        digipot9_set_wiper_1 ( &digipot9, cnt );
        digipot9_set_wiper_2 ( &digipot9, cnt );
        log_printf( &logger, " * Wipers position set to %u *\r\n", cnt );

        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.DIGIPOT9

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. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.