writeSPI works to transmit the configuration paramater for the ADS1118 and receive the ADC conversion result from the ADS1118.
ADS.writeSPI(value, 0); //sets to mode 0
ADS.writeSPI(value, 1); //sets to mode 1
config - configuration paramamter of the ADS1118’s register mode - an int that should pass either a '0' or a '1'
ADC result