MC68HC908AZ60 Datasheet, PDF (428/480 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Analog-to-Digital Converter (ADC-15)
I/O Signals
The ADC module has 15 channels that are shared with I/O ports B and
D. Refer to ADC Characteristics on page 439 for voltages referenced
below.
ADC Analog
Power Pin
(V_DDAREF)/ADC
Voltage
Reference Pin
(V_REFH)
NOTE:
The ADC analog portion uses V_DDAREF as its power pin. Connect the
V_DDA/V_DDAREF pin to the same voltage potential as V_DD. External
filtering may be necessary to ensure clean V_DDAREF for good results.
V_REFH is the high reference voltage for all analog-to-digital conversions.
Route V_DDAREF carefully for maximum noise immunity and place bypass
capacitors as close as possible to the package. V_DDAREF must be
present for operation of the ADC.
ADC Analog
Ground Pin
(V_SSA)/ADC
Voltage
Reference Low Pin
(V_REFL)
The ADC analog portion uses V_SSA as its ground pin. Connect the V_SSA
pin to the same voltage potential as V_SS.
V_REFL is the lower reference supply for the ADC.
ADC Voltage In
(ADCVIN)
ADCVIN is the input voltage signal from one of the 15 ADC channels to
the ADC module.
MC68HC908AZ60 — Rev 2.0
426
Analog-to-Digital Converter (ADC-15)
6-adc-15
MOTOROLA