Holtek HT66F0175 - Page 51

Rev. 1.50 50 August 28, 2017 Rev. 1.50 51 August 28, 2017
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
NORMAL Mode to SLOW Mode Switching
WhenrunningintheNORMALMode,whichusesthehighspeedsystemoscillator,andtherefore
consumesmorepower,thesystemclockcanswitchtorunintheSLOWModebysettheHLCLKbit
to“0”andsettheCKS2~CKS0bitsto“000”or“001”intheSMODregister.Thiswillthenusethe
lowspeedsystemoscillatorwhichwillconsumelesspower.Usersmaydecidetodothisforcertain
operationswhichdonotrequirehighperformanceandcansubsequentlyreducepowerconsumption.
TheSLOWModeissourcedfromtheLXTorLIRCoscillatordeterminedbytheconfiguration
optionandthereforerequiresthisoscillatortobestablebeforefullmodeswitchingoccurs.Thisis
monitoredusingtheLTObitintheSMODregister.
NORMAL Mode
SLOW Mode
CKS2~CKS0 = 00xB &
HLCLK = 0
SLEEP0 Mode
IDLEN=0
HALT instruction is executed
SLEEP1 Mode
IDLE0 Mode
IDLE1 Mode
WDT and LVD are all off
IDLEN=0
HALT instruction is executed
WDT is on
IDLEN=1, FSYSON=0
HALT instruction is executed
IDLEN=1, FSYSON=1
HALT instruction is executed