HT66F016 View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F016' PDF : 116 Pages View PDF
HT66F016/HT66F017/HT68F016/HT68F017
HT66F016R/HT66F017R/HT68F016R/HT68F017R
Together with fSYS/4 it is also used as one of the clock
sources for the Watchdog timer. The fTBC clock is used
as a source for the Time Base interrupt functions and for
the TMs.
System Operation Modes
There are six different modes of operation for the
microcontroller, each one with its own special character-
istics and which can be chosen according to the specific
performance and power requirements of the applica-
tion. 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.
Operation Mode
CPU
Description
fSYS
fSUB
fS
fTBC
NORMAL Mode
On
fH~ fH/64
On
On
On
SLOW Mode
On
fL
On
On
On
IDLE0 Mode
Off
Off
On
On
On
IDLE1 Mode
Off
On
On
On
On
SLEEP0 Mode
Off
Off
Off
Off
Off
SLEEP1 Mode
Off
Off
On
On
Off
· NORMAL Mode
As the name suggests this is one of the main operat-
ing 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 or HIRC oscilla-
tors. The high speed oscillator will however first be di-
vided by a ratio ranging from 1 to 64, the actual ratio
being selected by the CKS2~LCKS0 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 oper-
ates normally although now with a slower speed clock
source. The clock source used will be from the low
speed oscillators LIRC. Running the microcontroller in
this mode allows it to run with much lower operating
currents. In the SLOW Mode, the fH is off.
· SLEEP0 Mode
The SLEEP Mode is entered when an HALT instruc-
tion is executed and when the IDLEN bit in the SMOD
register is low. In the SLEEP0 mode the CPU will be
stopped, and the fSUB and fS clocks will be stopped too,
and the Watchdog Timer function is disabled. In this
mode, the LVDEN is must set to ²0². If the LVDEN is
set to ²1², it won¢t enter the SLEEP0 Mode.
· SLEEP1 Mode
The SLEEP Mode is entered when an HALT instruc-
tion is executed and when the IDLEN bit in the SMOD
register is low. In the SLEEP1 mode the CPU will be
stopped. However the fSUB and fS clocks will continue
to operate if the LVDEN is ²1² or the Watchdog Timer
function is enabled and if its clock source is chosen
via configuration option to come from the fSUB.
· IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction
is executed and when the IDLEN bit in the SMOD reg-
ister is high and the FSYSON bit in the CTRL 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 Watch-
dog Timer and TMs. In the IDLE0 Mode, the system
oscillator will be stopped.
· IDLE1 Mode
The IDLE1 Mode is entered when a HALT instruction
is executed and when the IDLEN bit in the SMOD reg-
ister is high and the FSYSON bit in the CTRL register
is high. In the IDLE1 Mode the system oscillator will be
inhibited from driving the CPU but may continue to
provide a clock source to keep some peripheral func-
tions operational such as the Watchdog Timer and
TMs. In the IDLE1 Mode, the system oscillator will
continue to run, and this system oscillator may be high
speed or low speed system oscillator.
Rev. 1.40
33
November 22, 2016
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