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HT66F03 View Datasheet(PDF) - Holtek Semiconductor

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HT66F03 Datasheet PDF : 139 Pages
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HT66F03/HT66F04/HT68F03/HT68F04
Fast Wake-up
To minimise power consumption the device can enter
the SLEEP or IDLE0 Mode, where the system clock
source to the device will be stopped. However when the
device is woken up again, it can take a considerable
time for the original system oscillator to restart, stabilise
and allow normal operation to resume. To ensure the
device is up and running as fast as possible a Fast
Wake-up function is provided, which allows fSUB,
namely either the LXT or LIRC oscillator, to act as a tem-
porary clock to first drive the system until the original
system oscillator has stabilised. As the clock source for
the Fast Wake-up function is fSUB, the Fast Wake-up
function is only available in the SLEEP1 and IDLE0
modes. When the device is woken up from the SLEEP0
mode, the Fast Wake-up function has no effect because
the fSUB clock is stopped. The Fast Wake-up enable/dis-
able function is controlled using the FSTEN bit in the
SMOD register.
If the HXT oscillator is selected as the NORMAL Mode
system clock, and if the Fast Wake-up function is en-
abled, then it will take one to two tSUB clock cycles of the
LIRC oscillator for the system to wake-up. The system
will then initially run under the fSUB clock source until
1024 HXT clock cycles have elapsed, at which point the
HTO flag will switch high and the system will switch over
to operating from the HXT oscillator.
If the ERC or HIRC oscillators or LIRC oscillator is used
as the system oscillator then it will take 15~16 clock cy-
cles of the ERC or HIRC or 1~2 cycles of the LIRC to
wake up the system from the SLEEP or IDLE0 Mode.
The Fast Wake-up bit, FSTEN will have no effect in
these cases.
System
Oscillator
HXT
ERC
HIRC
LIRC
LXT
FSTEN
Bit
0
Wake-up Time
(SLEEP0 Mode)
1024 HXT cycles
1
1024 HXT cycles
X 15~16 ERC cycles
X 15~16 HIRC cycles
X
1~2 LIRC cycles
X
1024 LTX cycles
Wake-up Time
(SLEEP1 Mode)
Wake-up Time
(IDLE0 Mode)
Wake-up Time
(IDLE1 Mode)
1024 HXT cycles
1~2 HXT cycles
1~2 fSUB cycles
(System runs with fSUB first for 1024 HXT cycles 1~2 HXT cycles
and then switches over to run with the HXT clock)
15~16 ERC cycles
1~2 ERC cycles
15~16 HIRC cycles
1~2 HIRC cycles
1~2 LIRC cycles
1~2 LIRC cycles
1024 LXT cycles
1~2 LXT cycles
Wake-Up Times
Note that if the Watchdog Timer is disabled, which means that the LXT and LIRC are all both off, then there will be no
Fast Wake-up function available when the device wakes-up from the SLEEP0 Mode.
NORM AL
fS Y S = fH ~ fH /6 4
fH o n
C P U ru n
fS Y S o n
fT B C o n
fS U B o n
SLEEP0
H A L T in s tr u c tio n is e x e c u te d
fS Y S o ff
C P U s to p
ID L E N = 0
fT B C o ff
fS U B o ff
W D T & L V D o ff
SLEEP1
H A L T in s tr u c tio n is e x e c u te d
fS Y S o ff
C P U s to p
ID L E N = 0
fT B C o ff
fS U B o n
W D T orLV D on
ID L E 1
H A L T in s tr u c tio n is e x e c u te d
C P U s to p
ID L E N = 1
FSYSO N =1
fS Y S o n
fT B C o n
fS U B o n
SLO W
fS Y S = fL
fL o n
C P U ru n
fS Y S o n
fT B C o n
fS U B o n
fH o ff
ID L E 0
H A L T in s tr u c tio n is e x e c u te d
C P U s to p
ID L E N = 1
FSYSO N =0
fS Y S o ff
fT B C o n
fS U B o n
Rev. 1.00
33
April 16, 2010
 

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