Datasheet

Advance Information MC68HC908GP20 — Rev 2.1
92 Freescale Semiconductor
5.7.1 ADC Analog Power Pin (V
DDAD
)/ADC Voltage Reference High Pin (V
REFH
)
The ADC analog portion uses V
DDAD
as its power pin. Connect the
V
DDAD
pin to the same voltage potential as V
DD
. External filtering may
be necessary to ensure clean V
DDAD
for good results.
NOTE: For maximum noise immunity, route V
DDAD
carefully and place bypass
capacitors as close as possible to the package.
5.7.2 ADC Analog Ground Pin (V
SSAD
)/ADC Voltage Reference Low Pin (V
REFL
)
The ADC analog portion uses V
SSAD
as its ground pin. Connect the
V
SSAD
pin to the same voltage potential as V
SS
.
NOTE: Route V
SSAD
cleanly to avoid any offset errors.
5.7.3 ADC Voltage In (ADV
IN
)
ADV
IN
is the input voltage signal from one of the eight ADC channels to
the ADC module.
5.8 I/O Registers
These I/O registers control and monitor ADC operation:
• ADC status and control register (ADSCR)
• ADC data register (ADR)
• ADC clock register (ADCLK)