MC68HC908GR16 Datasheet, PDF (49/310 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Analog-to-Digital Converter (ADC)
Functional Description
3.3.2 Voltage Conversion
NOTE:
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.
The ADC input voltage must always be greater than V_SSA and less than V_DDA.
Connect the V_DDA pin to the same voltage potential as the V_DD pin, and connect
the V_SSA pin to the same voltage potential as the V_SS pin.
The V_DDA pin should be routed carefully for maximum noise immunity.
INTERNAL
DATA BUS
READ DDRBx
WRITE DDRBx
RESET
WRITE PTBx
READ PTBx
DDRBx
PTBx
DISABLE
PTBx
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
MC68HC908GR16 — Rev. 1.0
MOTOROLA
Analog-to-Digital Converter (ADC)
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Data Sheet
49