Datasheet

Chapter 14 Analog-to-Digital Converter (S08ADC10V1)
MC9S08AW60 Data Sheet, Rev 2
Freescale Semiconductor 235
14.2.2.1 Analog Pin Enables
The ADC on MC9S08AW60 Series contains only two analog pin enable registers, APCTL1 and APCTL2.
14.2.2.2 Low-Power Mode Operation
The ADC is capable of running in stop3 mode but requires LVDSE and LVDE in SPMSC1 to be set.
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
.IfV
TEMP
is greater than V
TEMP25
the cold slope value is applied in Equation 14-1.IfV
TEMP
is
less than V
TEMP25
the hot slope value is applied in Equation 14-1.