Library Description

The library covers all the necessary functions that enables the usage of the R Meter click board.
It offers reading from output register and calculations that result in relatively accurate resistance value.

Key functions:

• uint16_t rmeter_dataRead() - Function is used to read data from output register.
• float rmeter_avgVolt() - Function is used to calculate average voltage value.
• float rmeter_getOhms() - Function is used to measure resistance of a resistor conected to the click board.

Examples description

The application is composed of the three sections :

• System Initialization - Initializes SPI module, LOG and GPIO structures, sets CS, RST, INT, PWM pins as output and AN pin as input.
• Application Initialization - Initalizes SPI driver and makes an initial log.
• Application Task - (code snippet) - This is an example that shows the capabilities of the R Meter click by measuring resistance. R Meter click is a handy tool but it’s not to be used as a precision instrument. The linearity of the OpAmp impacts the measurement.

void applicationTask()
{
    float ohms;
    char logTxt[ 20 ];
    
    ohms = rmeter_getOhms();
    
    if( ohms == 0 )
    {
        mikrobus_logWrite( " Over range! ", _LOG_LINE );
    }
    else
    {
        FloatToStr( ohms, logTxt );
        mikrobus_logWrite( "Resistance: ", _LOG_TEXT );
        mikrobus_logWrite( logTxt, _LOG_TEXT );
        mikrobus_logWrite( "ohm ", _LOG_LINE );
    }
    mikrobus_logWrite( "-----------------------", _LOG_LINE );
    Delay_ms( 500 );
}

Other mikroE Libraries used in the example:

• SPI
• UART
• Conversions

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.