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Rev. 1.20
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Rev. 1.20
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HT69F30A/HT69F40A/HT69F50A
TinyPower
TM
I/O Flash 8-Bit MCU with LCD & EEPROM
HT69F30A/HT69F40A/HT69F50A
TinyPower
TM
I/O Flash 8-Bit MCU with LCD & EEPROM
System Operation Modes
There are six different modes of operation for the microcontroller, each one with its own
special characteristics and which can be chosen according to the specific performance and
power requirements of the application. There are two modes allowing normal operation of the
microcontroller, the NORMAL Mode and SLOW Mode. The remaining four modes, the SLEEP0,
SLEEP1, IDLE0 and IDLE1 Mode are used when the microcontroller CPU is switched off to
conserve power.
Operating Mode
Description
CPU
f
SYS
f
SUB
f
S
N�RMAL Mode
�n
f
H
~f
H
/64
�n
�n
SL�W Mode
�n
f
SUB
�n
�n
IDLE0 Mode
�ff
�ff
�n
�n
IDLE1 Mode
�ff
�n
�n
�n
SLEEP0 Mode
�ff
�ff
�ff
�ff
SLEEP1 Mode
�ff
�ff
�n
�n
NORMAL Mode
As the name suggests this is one of the main operating modes where the microcontroller has all of
its functions operational and where the system clock is provided by one of the high speed oscillators.
This mode operates allowing the microcontroller to operate normally with a clock source will
come from one of the high speed oscillators, either the HXT, ERC, EC or HIRC oscillators. The
high speed oscillator will however first be divided by a ratio ranging from 1 to 64, the actual ratio
being selected by the CKS2~CKS0 and HLCLK bits in the SMOD register. Although a high speed
oscillator is used, running the microcontroller at a divided clock ratio reduces the operating current.
SLOW Mode
This is also a mode where the microcontroller operates normally although now with a slower speed
clock source. The clock source used will be from one of the low speed oscillators, either the LXT
or the LIRC. Running the microcontroller in this mode allows it to run with much lower operating
currents. In the SLOW Mode, the f
H
is off.
SLEEP0 Mode
The SLEEP Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP0 mode the CPU will be stopped, and the f
SUB
and f
S
clocks will
be stopped too, and the Watchdog Timer function is disabled. In this mode, the LVDEN is must set
to "0". If the LVDEN is set to "1", it won't enter the SLEEP0 Mode.
SLEEP1 Mode
The SLEEP1 Mode is entered when an HALT instruction is executed and when the IDLEN bit in the
SMOD register is low. In the SLEEP1 mode the CPU will be stopped. However the f
S
will continue
to operate if the LVDEN is “1” or the Watchdog Timer function is enabled as its clock source is from
the f
SUB
.
IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction is executed and when the IDLEN bit in the
SMOD register is high and the FSYSON bit in the SMOD1 register is low. In the IDLE0 Mode the
system oscillator will be inhibited from driving the CPU but some peripheral functions will remain
operational such as the Watchdog Timer, TMs and LCD driver. In the IDLE0 Mode, the system
oscillator will be stopped while the Watchdog Timer clock, f
S
, will be on.