HT48R05A-1/HT48C05/HT48R06A-1/HT48C06/HT48R08A-1
Options
The following table shows all kinds of options in the microcontroller. All of the options must be defined to ensure proper
system functioning.
Items
Options
1
2
3
4
5
6
7
8
WDT clock source: WDTOSC or fSYS/4
WDT function: enable or disable
LVR function: enable or disable
CLRWDT instruction(s): one or two clear WDT instruction(s)
System oscillator: RC or crystal
Pull-high resistors (PA~PC): none or pull-high
BZ function: enable or disable
PA0~PA7 wake-up: enable or disable
Application Circuits
V
D
D
V
D
D
V
D
D
R
e
s
e
t
1
0
0
k
W
P
A
0
~
P
A
7
C
i
r
c
u
i
t
R
4
O
S
C
R
C
S
y
s
t
e
m
O
s
c
i
l
l
a
t
o
r
m
0 . 1 F
R
E
S
2
W
O
S
C
W
O
O
S
S
C
C
1
2
P
B
0
/
/
B
Z
7
0
p
F
P
B
1
B
Z
m
0 . 1 F
P
B
2
N
M
O
S
o
p
e
n
d
r
a
i
n
C
1
V
S
S
P
C
0
/
I
N
T
O
O
S
S
C
C
1
2
P
C
1
/
T
M
R
C
S
r
y
s
t
a
l
/
R
e
s
o
n
a
t
o
r
R
1
y
s
t
e
m
O
s
c
i
l
l
a
t
o
r
C
2
O
O
S
S
C
C
1
2
O
S
C
F
o
r
R
1
,
C
1
,
C
2
s
e
e
n
o
t
e
C
i
r
c
u
i
t
H
T
4
8
R
0
5
A
-
1
/
H
T
4
8
8
C
0
5
O
S
C
C
i
r
c
u
i
t
H
T
4
8
R
0
6
A
-
1
/
H
T
4
C
0
6
H
T
4
8
R
0
8
A
-
1
Note: 1. Crystal/resonator system oscillators
For crystal oscillators, C1 and C2 are only required for some crystal frequencies to ensure oscillation. For
resonator applications C1 and C2 are normally required for oscillation to occur. For most applications it is not
necessary to add R1. However if the LVR function is disabled, and if it is required to stop the oscillator when
VDD falls below its operating range, it is recommended that R1 is added. The values of C1 and C2 should be
selected in consultation with the crystal/resonator manufacturer specifications.
2. Reset circuit
The reset circuit resistance and capacitance values should be chosen to ensure that VDD is stable and re-
mains within its operating voltage range before the RES pin reaches a high level. Ensure that the length of
the wiring connected to the RES pin is kept as short as possible, to avoid noise interference.
3. For applications where noise may interfere with the reset circuit and for details on the oscillator external com-
ponents, refer to Application Note HA0075E for more information.
Rev. 1.50
16
August 22, 2007
HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
