HT45R38
C to F Application Circuit 2
P
B
0
~
P
B
7
L
E
D
D
i
s
p
l
a
y
P
C
0
~
P
C
7
V
D
D
P
A
0
/
P
P
W
M
0
m
0 . 0 1 F *
V
R
D
D
P
A
1
/
W
M
1
2
P
A
1
0
0
k
P
A
3
/
I
N
N
T
T
0
P
A
4
/
I
1
E
S
m
0 . 1 F
P
A
5
/
/
T
M
R
0
1
7
1
0
k
P
A
6
T
M
R
P
A
m
0 . 1 F *
C
C
s
s
e
e
n
n
s
s
o
o
r
r
1
2
R
C
1
V
S
S
R
C
2
O
O
S
S
C
C
1
2
O
S
C
C
i
r
c
u
i
t
C
s
e
n
s
o
r
V
D
D
R
C
1
2
S
e
e
R
i
g
h
t
S
i
d
e
R
O
S
C
R
C
O
U
T
R
C
S
y
s
t
e
m
O
s
c
i
l
l
a
t
o
r
P
E
0
/
A
N
0
/
O
P
O
2
4
k
W
<
R
O
S
C
<
1
M
I
N
O
O
S
S
C
C
1
2
*
R
C
4
7
0
p
F
O
P
N
R
C
R
R
E
E
F
F
S
Y
S
O
P
P
C
1
*
O
S
C
1
P
E
1
/
A
N
1
~
P
E
4
/
A
N
4
C
r
y
s
t
a
l
S
y
s
t
e
m
O
s
c
i
l
l
a
t
o
r
F
s
o
r
t
h
e
v
a
l
u
e
s
,
C
2
e
e
t
a
b
l
e
b
e
l
o
w
O
S
C
2
R
1
H
T
4
5
R
3
8
O
S
C
C
i
r
c
u
i
t
The following table shows the C1, C2 and R1 values corresponding to the different crystal values. (For reference only)
Crystal or Resonator
4MHz Crystal
C1, C2
10pF
10pF
10pF
10pF
10pF
25pF
25pF
35pF
68pF
300pF
300pF
300pF
300pF
R1
12kW
4.3kW
10kW
4.7kW
12kW
10kW
15kW
15kW
15kW
12kW
12kW
12kW
12kW
8MHz Crystal
4MHz Resonator
8MHz Resonator
3.58MHz Crystal
3.58MHz Resonator
2MHz Crystal
2MHz Resonator
1MHz Crystal
480kHz Resonator
455kHz Resonator
429kHz Resonator
400kHz Resonator
The function of the resistor R1 is to ensure that the oscillator will switch off should low voltage conditions occur.
Such a low voltage, as mentioned here, is one which is less than the lowest value of the MCU operating volt-
age. Note however that if the LVR is enabled then R1 can be removed.
Note: The resistance and capacitance for the reset circuit should be designed in such a way as to ensure that the VDD
is stable and remains within a valid operating voltage range before bringing RES 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 ²*R² resistance and ²*C² capacitance should be consideration for the frequency of RC OSC.
Rsensor1~Rsensor12 are the resistance sensors.
Csensor1~Csensor12 are the capacitance sensors.
Rev. 1.00
32
December 13, 2006
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
