MC908GR32AVFAE Datasheet, PDF (61/314 Pages) Freescale Semiconductor, Inc – Microcontrollers

INTERNAL
DATA BUS
READ DDRx
WRITE DDRx
RESET
WRITE PTx
READ PTx
DDRx
PTx
Functional Description
DISABLE
PTx
ADC CHANNEL x
ADC DATA REGISTER
DISABLE
CONVERSION
INTERRUPT ^COMPLETE
ADC
LOGIC
ADC
VOLTAGE IN
(V_ADIN)
CHANNEL
SELECT
ADCH4–ADCH0
AIEN COCO
CGMXCLK
BUS CLOCK
ADC CLOCK
CLOCK
GENERATOR
ADIV2–ADIV0 ADICLK
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.
MC68HC908GR60A • MC68HC908GR48A • MC68HC908GR32A Data Sheet, Rev. 5
Freescale Semiconductor
61