Revised 08/03
7
TECHNICAL INFORMATION FOR FIC98648
4-10 Line test mode (Pin No. 4)
A line test mode can be activated by the input of an
“L” signal to port R70 at the moment of power supply.
Operation of the microprocessor and the surrounding
circuits will be tested according to the schedule
shown in Table 7. After powering on, signal outputs
change from Step 1 to Step 4 according to the table,
with Steps 1-3 lasting 5 seconds each. Afterwards,
Step 4 outputs will be maintained continuously until
the power is shut off.
l
a
n
i
m
r
e
T
t
u
p
t
u
O
l
a
n
g
i
S
e
m
a
N
l
o
b
m
y
S
.
o
N
n
i
P
1
p
e
t
S
2
p
e
t
S
3
p
e
t
S
4
p
e
t
S
O
C 2
n
o
i
t
a
r
t
n
e
c
n
o
c
l
a
n
g
i
s
1
9
R5
2
)
m
p
p
(
1
d
C
1
*
e
t
o
N
)
m
p
p
(
1
d
C)
m
p
p
(
1
d
C)
m
p
p
(
1
d
C
l
a
n
g
i
s
s
a
i
B
2
*
e
t
o
N
0
9
R4
20
5
5
28
2
18
2
1
D
E
L
n
e
e
r
G3
6
R9
1L
H
(
3
e
t
o
N
)H
D
E
L
d
e
R2
6
R8
1H
L
(
4
e
t
o
N
)H
l
o
r
t
n
o
c
r
e
p
m
a
D
l
a
n
g
i
s
0
6
R6
1H
L
(
5
e
t
o
N
)H
n
o
i
t
c
n
u
f
l
a
M1
6
R7
1H
L
(
6
e
t
o
N
)H
k
r
a
m
h
c
n
e
B
s
u
t
a
t
s
l
a
w
e
n
e
r
2
9
R6
2
HLH
H
Notes:
(1) Please refer to Sec. 4-1-4 - Input signal for damper control
(2) Please refer to Sec. 4-4 - Bias signal output
(3) H or L, as input to Pin #10 for initial warmup setting - refer to Sec. 4-1-1
(4) H or L, as input to Pin #11 for benchmark adjustment - refer to Sec. 4-1-2
(5) H or L, as input to Pin #12 for benchmark adjustment - refer to Sec. 4-1-2
(6) H or L, as input to Pin #13 for benchmark reset - refer to Sec. 4-1-3
(7) Outputs shown are held until power is shut off
Table 7 - Line test mode
5. Electrical Circuit for FIC98648
The following peripheral circuits are suggested when
using the FIC98648 with the TGS4160 sensor.
5-1 Circuit for driving sensor and for processing sensor signals
The block/circuit diagrams for driving the sensor and
processing its signals are shown in Figure 3 (below)
and Figure 4 (Page 8) respectively. Please note the
following items:
a) +5.0V should be applied to Pin No. 6 for the heater
of TGS4160.
b) +3.8V is the specified voltage to sensor pin No. 5
for the built-in thermistor which is connected in
series with an 8.2kΩ resistor. Output voltage across
the 8.2kΩ resistor is designed to be input to port
Thermistor
signal (VT)
FIC98648
Heater
voltage
(VH)
Sensor
voltage
(EMF)
Buffer
circuit
4.5 times
amplification
circuit
+3.8V
+5V
Regulation
circuit
Bias signal (PWM signal)
Convert to DC
Buffer
circuit
+
10 times
amplification
circuit
+
Figure 3 - Block diagram for driving sensor and processing sensor signal