mc68hc908ap8a Freescale Semiconductor, Inc, mc68hc908ap8a Datasheet - Page 250

• Manufacturer Part Number: mc68hc908ap8a
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Analog-to-Digital Converter (ADC)
15.5.1 Wait Mode
The ADC continues normal operation in wait mode. Any enabled CPU interrupt request from the ADC can
bring the MCU out of wait mode. If the ADC is not required to bring the MCU out of wait mode, power
down the ADC by setting the ADCH[4:0] bits to logic 1’s before executing the WAIT instruction.
15.5.2 Stop Mode
The ADC module is inactive after the execution of a STOP instruction. Any pending conversion is aborted.
ADC conversions resume when the MCU exits stop mode. Allow one conversion cycle to stabilize the
analog circuitry before attempting a new ADC conversion after exiting stop mode.
15.6 I/O Signals
The ADC module has eight channels shared with port A I/O pins.
15.6.1 ADC Voltage In (V
V
15.6.2 ADC Analog Power Pin (V
The ADC analog portion uses V
as V
15.6.3 ADC Analog Ground Pin (V
The ADC analog portion uses V
as V
15.6.4 ADC Voltage Reference High Pin (V
V
voltage potential as V
Specifications).
15.6.5 ADC Voltage Reference Low Pin (V
V
V
250
ADIN
REFH
REFL
SSA
DD
SS
. There will be a finite current associated with V
is the input voltage signal from one of the eight ADC channels to the ADC module.
is the lower reference supply for the ADC. Connect the V
.
. External filtering may be necessary to ensure clean V
is the power supply for setting the reference voltage V
Route V
capacitors as close as possible to the package.
Route V
capacitors as close as possible to the package.
DDA
DDA
REFH
. There will be a finite current associated with V
carefully for maximum noise immunity and place bypass
carefully for maximum noise immunity and place bypass
ADIN
SSA
DDA
MC68HC908AP A-Family Data Sheet, Rev. 3
)
as its ground pin. Connect the V
as its power pin. Connect the V
DDA
SSA
)
)
NOTE
NOTE
REFL
REFH
REFL
)
)
(see
REFH
DDA
Chapter 22 Electrical
REFL
. Connect the V
for good results.
DDA
SSA
pin to the same voltage potential as
pin to the same voltage potential
pin to the same voltage potential
REFH
(see
REFH
Chapter 22 Electrical
Freescale Semiconductor
Specifications).
pin to the same