Calibrating at 25°C will improve accuracy to ±4.5°C.Calibration at three points -40°C, 25°C, and 105°C will improve accuracy to ±2.5°C.After calibration has been completed, you will need to calculate the slope for both hotand cold. In application code, you can calculate the temperature as detailed above anddetermine if it is above or below 25°C. After you have determined whether thetemperature is above or below 25 °C. you can recalculate the temperature using the hot orcold slope value obtained during calibration.17.2 IntroductionThe 12-bit analog-to-digital converter (ADC) is a successive approximation ADCdesigned for operation within an integrated microcontroller system-on-chip.17.2.1 FeaturesFeatures of the ADC module include:• Linear Successive Approximation algorithm with 8-, 10-, or 12-bit resolution• Up to 8 external analog inputs, external pin inputs, and 5 internal analog inputsincluding internal bandgap, temperature sensor, and references• Output formatted in 8-, 10-, or 12-bit right-justified unsigned format• Single or Continuous Conversion (automatic return to idle after single conversion)• Support up to eight result FIFO with selectable FIFO depth• Configurable sample time and conversion speed/power• Conversion complete flag and interrupt• Input clock selectable from up to four sources• Operation in Wait or Stop modes for lower noise operation• Asynchronous clock source for lower noise operation• Selectable asynchronous hardware conversion trigger• Automatic compare with interrupt for less-than, or greater-than or equal-to,programmable valueChapter 17 Analog-to-digital converter (ADC)MC9S08SU16 Reference Manual, Rev. 5, 4/2017NXP Semiconductors 259
