HT67F60 datasheet(68/242 Pages) HOLTEK

68 / 242 page

Rev. 1.50

March 06 , 2012

Rev. 1.50

March 06 , 2012

HT67F30/HT67F40/HT67F50/HT67F60

TinyPowerTM A/D Flash Type 8-Bit MCU with LCD & EEPRO

Wake-up

After the system enters the SLEEP or IDLE Mode, it can be woken up from one of various sources

listed as follows:

● An external reset

● An external falling edge on Port A

● A system interrupt

● A WDT overflow

If the system is woken up by an external reset, the device will experience a full system reset,

however, if the device is woken up by a WDT overflow, a Watchdog Timer reset will be initiated.

Although both of these wake-up methods will initiate a reset operation, the actual source of the

wake-up can be determined by examining the TO and PDF flags. The PDF flag is cleared by a

system power-up or executing the clear Watchdog Timer instructions and is set when executing the

"HALT" instruction. The TO flag is set if a WDT time-out occurs, and causes a wake-up that only

resets the Program Counter and Stack Pointer, the other flags remain in their original status.

Each pin on Port A can be setup using the PAWU register to permit a negative transition on the pin

to wake-up the system. When a Port A pin wake-up occurs, the program will resume execution at the

instruction following the "HALT" instruction. If the system is woken up by an interrupt, then two

possible situations may occur. The first is where the related interrupt is disabled or the interrupt is

enabled but the stack is full, in which case the program will resume execution at the instruction

following the "HALT" instruction. In this situation, the interrupt which woke-up the device will not

be immediately serviced, but will rather be serviced later when the related interrupt is finally enabled

or when a stack level becomes free. The other situation is where the related interrupt is enabled and

the stack is not full, in which case the regular interrupt response takes place. If an interrupt request

flag is set high before entering the SLEEP or IDLE Mode, the wake-up function of the related

interrupt will be disabled.

Programming Considerations

The HXT and LXT oscillators both use the same SST counter. For example, if the system is woken

up from the SLEEP0 Mode and both the HXT and LXT oscillators need to start-up from an off state.

The LXT oscillator uses the SST counter after HXT oscillator has finished its SST period.

● If the device is woken up from the SLEEP0 Mode to the NORMAL Mode, the high speed system

oscillator needs an SST period. The device will execute first instruction after HTO is "1". At this

time, the LXT oscillator may not be stability if fSUB is from LXT oscillator. The same situation

occurs in the power-on state. The LXT oscillator is not ready yet when the first instruction is

executed.

● If the device is woken up from the SLEEP1 Mode to NORMAL Mode, and the system clock

source is from HXT oscillator and FSTEN is "1" , the system clock can be switched to the LXT or

LIRC oscillator after wake up.

● There are peripheral functions, such as WDT, TMs and SPIA, LCD driver and SIM, for which the

fSYS is used. If the system clock source is switched from fH to fL, the clock source to the peripheral

functions mentioned above will change accordingly.

● The on/off condition of fSUB and fS depends upon whether the WDT is enabled or disabled as the

WDT clock source is selected from fSUB.

HT67F60 датащи(PDF) 68 Page - Holtek Semiconductor Inc

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