MC9S08SG32E1JTGR FREESCALE [Freescale Semiconductor, Inc], MC9S08SG32E1JTGR Datasheet - Page 123

• Manufacturer Part Number: MC9S08SG32E1JTGR
• Description: HCS08 Microcontrollers
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Equation 9-1
where:
For temperature calculations, use the V
In application code, the user reads the temperature sensor channel, calculates V
V
less than V
calibrate the bandgap voltage reference and temperature sensor.
Calibrating at 25°C will improve accuracy to
Calibration at three points, -40°C, 25°C, and 125°C will improve accuracy to ± 2.5°C. Once calibration
has been completed, the user will need to calculate the slope for both hot and cold. In application code, the
user would then calculate the temperature using
temperature is above or below 25°C. Once determined if the temperature is above or below 25°C, the user
can recalculate the temperature using the hot or cold slope value obtained during calibration.
Freescale Semiconductor
TEMP25
— By using the calculated value of V
— V
— V
— m is the hot or cold voltage versus temperature slope in V/°C.
. If V
TEMP25
TEMP
TEMP25
provides an approximate transfer function of the temperature sensor.
TEMP
is the voltage of the temperature sensor channel at the ambient temperature.
the hot slope value is applied in
is greater than V
is the voltage of the temperature sensor channel at 25°C.
Temp = 25 - ((V
TEMP25
MC9S08SG32 Data Sheet, Rev. 7
TEMP25
the cold slope value is applied in
±
DD
TEMP
4.5°C.
and m values from the ADC Electricals table.
Equation 9-1
, convert the digital value of AD26 into a voltage,
-V
Equation
TEMP25
) ÷ m)
9-1. To improve accuracy the user should
as detailed above and then determine if the
Chapter 9 Analog-to-Digital Converter (S08ADC10V1)
Equation
TEMP
, and compares to
9-1. If V
TEMP
Eqn. 9-1
V
TEMP
123
is