HT68F13 datasheet(44/161 Pages) HOLTEK

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LowVoltageReset

- LVR

The microcontroller contains a low voltage reset circuit in order to monitor the supply voltage of the

device. The LVR function is selected via a configuration option. If the supply voltage of the device

drops to within a range of 0.9V~VLVR such as might occur when changing the battery, the LVR will

automatically reset the device internally. For a valid LVR signal, a low supply voltage, i.e., a voltage in the

range between 0.9V~VLVR must exist for a time greater than that specified by tLVR in the A.C. characteristics.

If the low supply voltage state does not exceed this value, the LVR will ignore the low supply voltage and

will not perform a reset function. The actual VLVR value can be selected via configuration options.

WatchdogTime-outResetduringNormalOperation

The Watchdog time-out Reset during normal operation is the same as a hardware RES pin reset except

that the Watchdog time-out flag TO will be set to

²1².

WatchdogTime-outResetduringSLEEPorIDLEMode

The Watchdog time-out Reset during SLEEP or IDLE Mode is a little different from other kinds of

reset. Most of the conditions remain unchanged except that the Program Counter and the Stack Pointer

will be cleared to

²0² and the TO flag will be set to ²1². Refer to the A.C. Characteristics for t

SST details.

Rev.1.10

February9,2011

HT68F13/HT68F14/HT68F15

EnhancedI/OFlashType MCU

L V R

I n t e r n a l R e s e t

t R S T D + t S S T

Note: tRSTD ispower-ondelay,typicaltime=100ms

LowVoltageResetTimingChart

t R S T D + t S S T

W D T T i m e - o u t

I n t e r n a l R e s e t

Note: tRSTD ispower-ondelay,typicaltime=100ms

WDT Time-outResetduringNormalOperationTimingChart

t S S T

W D T T i m e - o u t

I n t e r n a l R e s e t

Note:

The tSST is15~16clockcyclesifthesystemclocksourceisprovidedby ERC or HIRC.

The tSST is1024clockfor HXT.The tSST is1~2clockfor LIRC.

WDT Time-outResetduringSLEEP orIDLETimingChart

HT68F13 Datasheet(PDF) 44 Page - Holtek Semiconductor Inc