MC68HC908GR16 Datasheet, PDF (117/310 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Data Sheet — MC68HC908GR16
Section 10. Low-Power Modes
10.1 Introduction
The microcontroller (MCU) may enter two low-power modes: wait mode and stop
mode. They are common to all HC08 MCUs and are entered through instruction
execution. This section describes how each module acts in the low-power modes.
10.1.1 Wait Mode
The WAIT instruction puts the MCU in a low-power standby mode in which the
central processor unit (CPU) clock is disabled but the bus clock continues to run.
Power consumption can be further reduced by disabling the low-voltage inhibit
(LVI) module through bits in the CONFIG1 register. See Section 5. Configuration
Register (CONFIG).
10.1.2 Stop Mode
Stop mode is entered when a STOP instruction is executed. The CPU clock is
disabled and the bus clock is disabled if the OSCENINSTOP bit in the CONFIG2
register is at a logic 0. See Section 5. Configuration Register (CONFIG).
10.2 Analog-to-Digital Converter (ADC)
10.2.1 Wait Mode
The analog-to-digital converter (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 ADCH4–ADCH0 bits in the ADC status and control
register before executing the WAIT instruction.
10.2.2 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
after an external interrupt. Allow one conversion cycle to stabilize the analog
circuitry.
MC68HC908GR16 — Rev. 1.0
MOTOROLA
Low-Power Modes
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Data Sheet
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