Rev. 1.71
44
April 11, 2017
Rev. 1.71
45
April 11, 2017
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
HT66F002/HT66F0025/HT66F003/HT66F004
Cost-Effective A/D Flash MCU with EEPROM
SLOW Mode to NORMAL Mode Switching
In SLOW Mode the system uses LIRC low speed system oscillator. To switch back to the NORMAL
Mode, where the high speed system oscillator is used, the HLCLK bit should be set to “1” or
HLCLK bit is “0”, but CKS2~CKS0 is set to “010”, “011”, “100”, “101”, “110” or “111”. As a
certain amount of time will be required for the high frequency clock to stabilise, the status of the
HTO bit is checked.
Entering the SLEEP0 Mode
There is only one way for the devices to enter the SLEEP0 Mode and that is to execute the “HALT”
instruction in the application program with the IDLEN bit in SMOD register equal to “0” and the
WDT off. When this instruction is executed under the conditions described above, the following will
occur:
• The system clock, WDT clock and Time Base clock will be stopped and the application program
will stop at the “HALT” instruction.
• The Data Memory contents and registers will maintain their present condition.
• The WDT will be cleared and stopped.
• The I/O ports will maintain their present conditions.
• In the status register, the Power Down flag, PDF, will be set and the Watchdog time-out flag, TO,
will be cleared.
