MC9S08AC16 Datasheet, PDF (252/338 Pages) Freescale Semiconductor, Inc – 8-Bit HCS08 Central Processor Unit (CPU)

Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
14.2.3 Temperature Sensor
The ADC1 module includes a temperature sensor whose output is connected to one of the ADC analog
channel inputs. Equation 14-1 provides an approximate transfer function of the temperature sensor.
Temp = 25 - ((V_TEMP -V_TEMP25) ÷ m)
Eqn. 14-1
where:
— V_TEMP is the voltage of the temperature sensor channel at the ambient temperature.
— V_TEMP25 is the voltage of the temperature sensor channel at 25°C.
— m is the hot or cold voltage versus temperature slope in V/°C.
For temperature calculations, use the V_TEMP25 and m values from the ADC Electricals table.
In application code, the user reads the temperature sensor channel, calculates V_TEMP, and compares to
V_TEMP25 . If V_TEMP is greater than V_TEMP25 the cold slope value is applied in Equation 14-1. If V_TEMP is
less than V_TEMP25 the hot slope value is applied in Equation 14-1.
For more information on using the temperature sensor, consult AN3031.
MC9S08AC16 Series Data Sheet, Rev. 0
252
PRELIMINARY
Freescale Semiconductor