PAC1921 click

PAC1921 click is a versatile power monitoring and measuring device intended for the high speed, low latency measurements. This device can measure current, voltage or the power of the connected load.

click Product page

Click library

• Author : MikroE Team
• Date : Jan 2020.
• Type : I2C type

Software Support

We provide a library for the PAC1921 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 form compilers IDE(recommended way), or downloaded from our LibStock, or found on mikroE github account.

Library Description

This library contains API for PAC1921 Click driver.

Standard key functions :

• Config Object Initialization function.

  void pac1921_cfg_setup ( pac1921_cfg_t *cfg );

• Initialization function.

  PAC1921_RETVAL pac1921_init ( pac1921_t ctx, pac1921_cfg_t cfg );

• Click Default Configuration function.

  void pac1921_default_cfg ( pac1921_t *ctx );

Example key functions :

• This function writes data to the specified register address/es and saves the state of the register/s so it doesn't write the same value/s twice.

  void pac1921_write_to_reg ( pac1921_t ctx, uint8_t reg_addr, uint8_t write_data, uint8_t len );

• This function gathers voltage/power data from the PAC1921 chip and, depending on the measurement mode, converts those raw values into a more suitable form.

  float pac1921_get_measured_data ( pac1921_t *ctx, uint8_t measurement_mode, uint8_t sample_num );

• This function sets the digital output on the interrupt pin.

  void pac1921_set_int_pin ( pac1921_t *ctx, uint8_t output );

Examples Description

This example showcases how to measure voltage, current or power (load) data using the PAC1921 chip. Required modules are first initialized and after used to read and display the measured data.

The demo application is composed of two sections :

Application Init

This function initializes and configures the logger and click modules. Default settings are written to three control/configuration registers in the default_cfg(...) function.

void application_init ( )
{
    log_cfg_t log_cfg;
    pac1921_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.

    pac1921_cfg_setup( &cfg );
    PAC1921_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    pac1921_init( &pac1921, &cfg );
    Delay_ms ( 100 );
    pac1921_default_cfg( &pac1921 );
    Delay_ms ( 100 );
}

Application Task

This function reads and displays voltage, current or power data from the chip, depending on the specified measurement mode and sample count. It does so every half a second.

void application_task ( )
{
    float read_data;

    read_data = pac1921_get_measured_data( &pac1921, PAC1921_MEASUREMENT_MODE_V_BUS_FREE_RUN,
                                                     PAC1921_SAMPLE_RATE_512 );

    if ( pac1921.aux.measurement_mode_old == PAC1921_MEASUREMENT_MODE_V_POWER_FREE_RUN )
    {
        log_printf( &logger, " * Power: %.2f W * \r\n", read_data );
    }
    else
    {
        log_printf( &logger, " * Voltage: %.2f mV * \r\n", read_data );
    }

    Delay_ms ( 500 );
} 

The full application code, and ready to use projects can be installed directly form compilers IDE(recommneded) or found on LibStock page or mikroE GitHub accaunt.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.PAC1921

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.