HT66F317 Datasheet, PDF (41/198 Pages) Holtek Semiconductor Inc – Enhanced A/D MCU with LCD Driver

HT66F317/HT66F318
Enhanced A/D MCU with LCD Driver
High Speed Os�illato�
HXT
fH
HIRC
High Speed Os�illato�
Configu�ation Option
�-stage P�es�ale�
fH/2
fH/4
fH/8
fH/1�
fH/�2
fH/�4
fL
Low Speed Os�illato�
LXT
fSUB
LIRC
HLCLK�
CKS2~CKS0 �its
Low speed Os�illato�
Configu�ation Option
System Clock Configurations
fSYS
Fast Wake-up f�o� SLEEP
Mode o� IDLE Mode Cont�ol
(fo� HXT only)
External Crystal/Ceramic Oscillator – HXT
The External Crystal/Ceramic System Oscillator is one of the high frequency oscillator choices,
which is selected via configuration option. For most crystal oscillator configurations, the simple
connection of a crystal across OSC1 and OSC2 will create the necessary phase shift and feedback for
oscillation, without requiring external capacitors. However, for some crystal types and frequencies,
to ensure oscillation, it may be necessary to add two small value capacitors, C1 and C2. Using a
ceramic resonator will usually require two small value capacitors, C1 and C2, to be connected as
shown for oscillation to occur. The values of C1 and C2 should be selected in consultation with the
crystal or resonator manufacturer’s specification.
For oscillator stability and to minimise the effects of noise and crosstalk, it is important to ensure
that the crystal and any associated resistors and capacitors along with interconnecting lines are all
located as close to the MCU as possible.
C1
O SC1
In te r n a l
O s c illa to r
C ir c u it
Rp
Rf
T o in te r n a l
C2
O SC2
c ir c u its
N o te : 1 . R p is n o r m a lly n o t r e q u ir e d . C 1 a n d C 2 a r e r e q u ir e d .
2 . A lth o u g h n o t s h o w n O S C 1 /O S C 2 p in s h a v e a p a r a s itic
c a p a c ita n c e o f a r o u n d 7 p F .
Crystal/Resonator Oscillator – HXT
Rev. 1.20
41
December 13, 2016