Analog-to-Digital Converter (ADC12)
MCF51CN128 Reference Manual, Rev. 6
Freescale Semiconductor
15-3
15.1.2.3
Hardware Trigger
The RTC on this device can be enabled as a hardware trigger for the ADC module by setting the
ADCSC2[ADTRG] bit. When enabled, the ADC is triggered every time RTCCNT matches RTCMOD.
The RTC interrupt does not have to be enabled to trigger the ADC.
The RTI can be configured to cause a hardware trigger in MCU run, wait, and stop3.
15.1.2.4
Temperature Sensor
The ADC module includes a temperature sensor whose output is connected to one of the ADC analog
channel inputs.
provides an approximate transfer function of the temperature sensor.
Temp = 25
-
((V
TEMP
-V
TEMP25
)
÷
m)
Eqn. 15-1
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 in the data sheet.