MC68HC08AZ16 Datasheet, PDF (494/527 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Appendix C: ADC-15
I/O Signals
I/O Signals
The ADC module has 15 channels that are shared with I/O ports B and
D and one channel with an input-only port bit on port D. Refer to ADC
Characteristics on page 398 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.
Connect the V_REFH pin to a voltage potential between 1.5 volts and
V_DDAREF/V_DDA depending on the desired upper conversion boundary.
Route V_DDAREF carefully for maximum noise immunity and place bypass
capacitors as close as possible to the package.
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.
7-adc15
MOTOROLA
Appendix C: ADC-15
MC68HC08AZ32
493