HT66F24D View Datasheet(PDF) - Holtek Semiconductor
Part Name
Description
MFG CO.
'HT66F24D' PDF : 177 Pages View PDF
A/D Flash Type 8-bit MCU with EEPROM
HT66F24D/HT66F25D
Hig� Speed Os�illato�
HXT
fH
HIRC
Hig� Speed Os�illato�
Configu�ation Option
LXT
fSUB
LIRC
fSUB Os�illato�
Configu�ation Option
6-stage P�es�ale�
fH/�
fH/4
fH/8
fH/16
fH/��
fH/64
fSYS
fSUB
HLCLK�
CKS�~CKS0 bits
Fast Wake-up f�om SLEEP
�ode o� IDLE �ode Cont�ol
(fo� HXT only)
System Clock Configurations
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.
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
Crystal Oscillator C1 and C2 Values
Crystal Frequency
C1
12MHz
0pF
8MHz
0pF
4MHz
0pF
1MHz
100pF
Note: C1 and C2 values are for guidance only.
Crystal Recommended Capacitor Values
C2
0pF
0pF
0pF
100pF
Rev. 1.10
37
March 25, 2013
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