NXP Semiconductors freescale K51 Series Reference Manual

31.4.10 MCU wait mode operationWait mode is a lower power-consumption standby mode from which recovery is fastbecause the clock sources remain active. If a conversion is in progress when the MCUenters Wait mode, it continues until completion. Conversions can be initiated while theMCU is in Wait mode by means of the hardware trigger or if continuous conversions areenabled.The bus clock, bus clock divided by two, and ADACK are available as conversion clocksources while in Wait mode. The use of ALTCLK as the conversion clock source in Waitis dependent on the definition of ALTCLK for this MCU. Refer to the ChipConfiguration information on ALTCLK specific to this MCU.If the compare and hardware averaging functions are disabled, a conversion completeevent sets the COCO and generates an ADC interrupt to wake the MCU from Wait modeif the respective ADC interrupt is enabled (AIEN=1). If the hardware averaging functionis enabled, the COCO will set (and generate an interrupt if enabled) when the selectednumber of conversions are completed. If the compare function is enabled, the COCO willset (and generate an interrupt if enabled) only if the compare conditions are met. If asingle conversion is selected and the compare trigger is not met, the ADC will return toits idle state and cannot wake the MCU from Wait mode unless a new conversion isinitiated by the hardware trigger.31.4.11 MCU Normal Stop mode operationStop mode is a low power-consumption standby mode during which most or all clocksources on the MCU are disabled.31.4.11.1 Normal Stop mode with ADACK disabledIf the asynchronous clock, ADACK, is not selected as the conversion clock, executing astop instruction aborts the current conversion and places the ADC in its idle state. Thecontents of the ADC registers, including Rn, are unaffected by Normal Stop mode. Afterexiting from Normal Stop mode, a software or hardware trigger is required to resumeconversions.Chapter 31 Analog-to-Digital Converter (ADC)K51 Sub-Family Reference Manual, Rev. 6, Nov 2011Freescale Semiconductor, Inc. 747