Library Description

Library offers a choice to communicate with the CO 2 Click board by writting to the registers and by reading from the registers via I2C interface. Library consists of functions which can read CO measured and converted data from the 12-bit AD converter. Library also can calculate CO digital value to the ppm value. For more details check documentation.

Key functions:

• uint8_t co2_writeReg( uint8_t register_address, uint8_t transfer_data ) - Function writes one byte to the register.

• uint8_t co2_readReg( uint8_t register_address, uint8_t *dataOut ) - Function reads one byte from the register.

• void co2_readADC( uint16_t *dataOut ) - Function reads converted data (CO) from the 12-bit AD converter.

• void co2_getCOppm( float *coData ) - Function reads CO converted data and calculates this value to the ppm.

Example description

The application is composed of three sections :

• System Initialization - Initializes peripherals and pins.
• Application Initialization - Initializes I2C interface and performs the device configuration for properly working.
• Application Task - (code snippet) - Gets CO (Carbon Monoxide) data as ppm value every 300 miliseconds. Results will be logged on UART. The CO value range is from 0 to 1000 ppm.

void applicationTask()
{
 co2_waitI2CReady();

 co2_getCOppm( &coValue );

 FloatToStr( coValue, text );
 cutFloat();
 mikrobus_logWrite( "CO : ", _LOG_TEXT );
 mikrobus_logWrite( text, _LOG_TEXT );
 mikrobus_logWrite( " ppm", _LOG_LINE );

 Delay_ms( 300 );
}

Additional Functions :

• void cutFloat() - This function is used to round up the value to two decimal places.

Other mikroE Libraries used in the example:

• I2C
• Conversions
• UART

Additional notes and information

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.