Holtek HT45F6530, Руководство пользователя

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Rev. 1.00 36 August 29, 2018 Rev. 1.00 37 August 29, 2018
HT45F6530
AC Voltage Regulator Flash MCU
HT45F6530
AC Voltage Regulator Flash MCU
Oscillators
Various oscillator options offer the user a wide range of functions according to their various
application requirements. The flexible features of the oscillator functions ensure that the best
optimisation can be achieved in terms of speed and power saving. Oscillator selections and operation
are selected through registers.
Oscillator Overview
In addition to being the source of the main system clock the oscillators also provide clock sources
for the Watchdog Timer and Time Base Interrupts. Two fully integrated internal oscillators, requiring
no external components, are provided to form a wide range of both fast and slow system oscillators.
The high frequency oscillator provides higher performance but carries with it the disadvantage of
higher power requirements, while the opposite is of course true for the lower frequency oscillator.
With the capability of dynamically switching between fast and slow system clock, the device has the
flexibility to optimise the performance/power ratio, a feature especially important in power sensitive
portable applications.
Type Name Frequency
Internal High Speed RC HIRC 8MHz
Internal Low Speed RC LIRC 32kHz
Oscillator Types
System Clock Configurations
There are two methods of generating the system clock, one high speed oscillator and one low speed
oscillator. The high speed oscillator is the internal 8MHz RC oscillator, known as the HIRC. The
low speed oscillator is the internal 32kHz RC oscillator, known as the LIRC. Selecting whether the
low or high speed oscillator is used as the system oscillator is implemented using the CKS2~CKS0
bits in the SCC register and as the system clock can be dynamically selected.
The frequency of the slow speed or high speed system clock is also determined using CKS2~CKS0
bits in the SCC register. Note that two oscillator selections must be made namely one high speed and
one low speed system oscillators. It is not possible to choose a no-oscillator selection for either the
high or low speed oscillator.
Prescaler
f
H
High Speed
Oscillator
Low Speed
Oscillator
f
H
/2
f
H
/16
f
H
/64
f
H
/8
f
H
/4
f
H
/32
CKS2~CKS0
f
SYS
f
SUB
f
SUB
f
LIRC
f
LIRC
SLEEP
IDLE0
IDLE2
SLEEP
HIRC HIRCEN
LIRC
System Clock Configurations