Datasheet

Functional Description
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Freescale Semiconductor 49
Figure 3-2. ADC Block Diagram
3.3.2 Voltage Conversion
When the input voltage to the ADC equals V
REFH
, the ADC converts the signal to $3FF (full scale). If the
input voltage equals V
REFL
, the ADC converts it to $000. Input voltages between V
REFH
and V
REFL
are a
straight-line linear conversion.
NOTE
The ADC input voltage must always be greater than V
SSAD
and less than
V
DDAD
.
Connect the V
DDAD
pin to the same voltage potential as the V
DD
pin, and
connect the V
SSAD
pin to the same voltage potential as the V
SS
pin.
The V
DDAD
pin should be routed carefully for maximum noise immunity.
INTERNAL
DATA BUS
READ DDRBx
WRITE DDRBx
RESET
WRITE PTBx
READ PTBx
PTBx
DDRBx
PTBx
INTERRUPT
LOGIC
CHANNEL
SELECT
ADC
CLOCK
GENERATOR
CONVERSION
COMPLETE
ADC
(V
ADIN
)
ADC CLOCK
CGMXCLK
BUS CLOCK
ADCH4–ADCH0
ADC DATA REGISTER
AIEN COCO
DISABLE
DISABLE
ADC CHANNEL x
ADIV2–ADIV0 ADICLK
VOLTAGE IN