Library have a signle configuration definition - MAX44009_ACCURACY. In case when it defined as 0, library will be compiled with the reduced accuracy. That means for Lux readings will be used single I2C transaction and a little less calculations will be made in cost of losing some precision in results. Eny other (non-zero) value will compile normal accuracy.
Include library, initialize I2C and then call MAX44009_GetLux() function to get Lux readings. The return of this function is the LUX value, measured in millilux (e.g. the value of 147520 represents 147.520 Lux).
This library uses only two hardware-dependent functions: MAX44009_WriteReg() and MAX44009_ReadReg() which communicates with the IC via I2C bus.
MAX44009_WriteReg() - writes a value to register of MAX44009. It should be able to transmit two bytes via I2C and then generate a STOP condition.
MAX44009_ReadReg() - reads a value of register of MAX44009. It should be able transmit a single byte via I2C, reads a single byte via I2C and then generate a STOP condition.