MC68HC908MR8 Datasheet, PDF (317/372 Pages) Motorola, Inc – Microcontrollers

Analog-to-Digital Converter (ADC)
Wait Mode
18.6 Wait Mode
The WAIT instruction can put the MCU in low power-consumption
standby mode.
The ADC continues normal operation during 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 ADCH[4:0] in the ADC status and control
register before executing the WAIT instruction.
18.7 Stop Mode
The STOP instruction can put the MCU in low power-consumption
standby mode.
The ADC module becomes inactive after the execution of a STOP
instruction. Any pending conversion is aborted. ADC conversions
resume when the MCU exits stop mode after an external interrupt. Allow
one conversion cycle to stabilize the analog circuitry after exiting stop
mode.
18.8 I/O Signals
The ADC module has seven input signals that are shared with port A.
18.8.1 ADC Voltage Reference Pin (V_REFH)
V_REFH is the power supply for setting the reference voltage. Connect the
V_REFH pin to the same voltage potential as V_DDA. There will be a finite
current associated with V_REFH.
NOTE: Route V_REFH carefully for maximum noise immunity and place bypass
capacitors as close as possible to the package.
MC68HC908MR8 — Rev 4.1
Freescale Semiconductor
Analog-to-Digital Converter (ADC)
Technical Data
317