FIC03272 Datasheet, PDF (9/14 Pages) List of Unclassifed Manufacturers – Microprocessor for handling signals from the TGS4161 carbon dioxide sensor

TECHNICAL INFORMATION FOR FIC03272
5-3 System reset circuit
Under normal operating conditions, an “H” signal is
continuously applied to the RESET port (Pin #3).
When an “L” signal is applied to the RESET port for
a period of one machine cycle or longer, the internal
logic circuit of FIC03272 and the micro-processor’s
program return to the same condition which exists
just after powering on the unit, effectively resetting
the system.
To perform the above described system reset function
automatically, a circuit such as that shown in Figure
6 is suggested. This kind of automatic system reset
circuit is useful in circumstances such as just after
powering on, after a momentary power interruption,
at the moment of recovery after a sudden drop of
voltage, etc. The microprocessor’s program some-
times does not run correctly in these cases due to a
malfunction of the internal logic circuit in the
processor. Manual resets help to assure normal
operation of the microprocessor’s program.
5-4 CO2 concentration signal circuit
Port 91 (Pin No. 25) outputs a PWM signal which
represents a CO2 concentration in the range between
400 and 3000ppm. Figure 7 illustrates a sample circuit
for converting a PWM signal to a linear output of 0~3V
+4.4V
2SA1015Y
1k
104
3.9k ^{4. 7 k} 103
FIC03272
28
VDD
3
RESET
14
VSS
Figure 6 - Reset circuit
DC. A delay of several seconds is anticipated in the
DC voltage concentration signal because a C-R
combination is used in the circuit. A 100Ω resistor is
connected in series to protect the external circuit from
excessive current.
5-5 Circuit for damper control signal
Figure 8 shows an example circuit in which an H/L
signal which is output from port R60 (Pin No. 16)
and converted to an On/Off signal for controlling
the opening/closing of a damper. A 100Ω resistor is
connected in series to protect the external circuit from
excessive current.
FIC03272
R91 ²⁵
22k
10k
1M
1M
2
1
3
10µ ^{LM 324N}
100
6.2V
Analog output (0~3V)
for CO2 concentration
FIC03272
R60 ¹⁶
1k
Figure 7 - CO2 concentration signal circuit
10k
2SA1015Y
100
10k
6. 2V
Revised 06/04
Figure 8 - Damper control circuit
Damper control signal
9