HT48C70-1(2004) データシートの表示（PDF） - Holtek Semiconductor
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HT48C70-1 Datasheet PDF : 40 Pages
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Application Circuits
V DD
0 .0 1 m F *
VDD
100kW
0 .1 m F
RES
10kW
0 .1 m F *
VSS
P A 0~P A 7
P B 0~P B 7
P C 0~P C 7
P D 0~P D 7
P E 0~P E 7
P F0~P F7
P G 0~P G 7
O SC
C ir c u it
S e e R ig h t S id e
O SC1
O SC2
IN T
TM R 0
TM R 1
H T 4 8 R 7 0 A -1 /H T 4 8 C 7 0 -1
HT48R70A-1/HT48C70-1
V DD
R O SC
470pF
O SC1
O SC2
N M O S o p e n d r a in
C1
O SC1
C2
R1
O SC2
R C S y s te m O s c illa to r
24kW < R OSC< 1M W
C r y s ta l S y s te m O s c illa to r
F o r th e v a lu e s ,
s e e ta b le b e lo w
O SC1
10pF
32768H z
In te r n a l R C O s c illa to r
w ith R T C
O SC2
O S C C ir c u it
Note:
The resistance and capacitance for reset circuit should be designed to ensure that the VDD is stable and re-
mains in a valid range of the operating voltage before bringing RES to high.
²*² Make the length of the wiring, which is connected to the RES pin as short as possible, to avoid noise
interference.
The following table shows the C1, C2 and R1 value according different crystal values. (For reference only)
Crystal or Resonator
C1, C2
R1
4MHz Crystal
0pF
10kW
4MHz Resonator
10pF
12kW
3.58MHz Crystal
0pF
10kW
3.58MHz Resonator
25pF
10kW
2MHz Crystal & Resonator
25pF
10kW
1MHz Crystal
35pF
27kW
480kHz Resonator
300pF
9.1kW
455kHz Resonator
300pF
10kW
429kHz Resonator
300pF
10kW
The function of the resistor R1 is to ensure that the oscillator will switch off should low voltage condi-
tions occur. Such a low voltage, as mentioned here, is one which is less than the lowest value of the
MCU operating voltage. Note however that if the LVR is enabled then R1 can be removed.
Rev. 1.60
20
June 9, 2004
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