HT45F43_IndependentVoiceTypeCOAlarm.pdf

Independent Voice Type CO Alarm
HT45F43
Characteristics
 MCU characteristics : internal 2x OPAs & 2x comparators, EEPROM,
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HIRC 4MHz + 32K LIRC reduces external component count
Sensor : electro-chemical sensor (ME2-CO)
Power supply : 9V alkaline battery
Standby current : typ. 22A, max. 28A
Low voltage detect : 7.5V
Self Test / Calibrate function
LEDs : red, yellow, green
Voice functions for : CO level, battery low etc.
Internal oscillator and reset circuitry for reduced external components
Internal OPA for sensor signal amplification -- no need for external amplifier
Watchdog wakes up MCU every 32 seconds -- checks CO level and battery
Operating Procedure
 Preheat description
One min. preheat time required at power on. Other operations implemented during
this time generate a Beep and System Malfunction voice output.
 CO level measurement function
WDT wake-up every 32 sec -- implements CO level check. > 30PPM alarm sounds
with - Beep + Beep Beep + CO level exceeds limit for 30 sec and LED1 flashes.
After 20 sec the alarm stops. Alarm cancelled by pressing key
 Switch activated auto test function
Short press : battery test, 1.65V voltage ref. test, CO sensor open circuit test
 During the battery low voltage test, the alarm will emit a Beep + Please change
the battery voice output and the green LED2 will flash once.
 If CO sensor open circuit or 1.65V voltage ref. out of range, then alarm emits a
Beep + System Malfunction voice and green LED2 flashes once.
 If the system is operating normally, then a Beep + System Normal voice output
will be generated and the red LED1 will flash once.
 Long switch press : voice test mode. All voice data output in sequence. Voice can
be stopped by pressing switch again.
 Calibration function
Hold the switch down and apply power to execute. Implements a 30PPM / 50PPM /
100PPM / 300PPM calibration -- yellow LED3 will flash. Flash 3 times with 0.5 sec
stop indicates 30PPM calibration and so on. The switch can be used to change the
calibration level. After the calibration has completed the system enters the normal
operating mode.
Application Circuit
CO Sensor Fixed Voltage
and Amplifier Circuit
Test and
Calibration Switch
U1
5
3V3
1.65V
R5
1M
100K
Q1
R8
C8050
1K
C1
PC1/AN5/OSC2
4
PA2/A1P
18
R7
TEST
PC2/OSC3
PA2/A1P/C2OUT
PA1/C1OUT/TMR0
OPA1
17
PA0/CNP/COM0
1K
1
R6
1M
ME2-CO
16
C
PC3/OSC4
PA4/A1E/TMR1
1K
PA0
3V3
J270
33K
15
R10
51K
3
PA5/A2P/PFD
Vin Vout
GND
3
3V3
20
PB3/AN0/SCS
PB1/SDI/SDA
PB2/SCK/SCL
PB0/SDO/INT1
VSS
VDD
PB6/AN3/RES
9
11
10
12
1
2
6
5
7
CE VDD
SO HD
SCK WP
SI VSS
8
7
3
4
RESET
C9
104
3V3
PC0/AN4/OSC1
3V3
2
8
6
4
-
AudIn CE
VDD OUTP
NC OUTN
VSS VREF
5
7
1
3
C7
V
6
1
/
U
1
9
3
7
V
2
8
T
H
HT45F43
Battery
Power Supply
R1 6
U3
r
e
k
a
e
p
S
C5
3
0
1
+
6
C8
R1 2
K
0
2
8
K
1
5
R1 5 C6
PB4/AN1/AUD/PCLK
LOW_BAT
3V3
U2
V
6
1
/
U
7
4
3
0
1
K
0
1
1
C4
22U /16V
Voice Flash
Memory
3V3
5
0
0
2
L
5
2
X
M
HT7533
C3
ICP
Interface
LED
Indicators
OPA2
R1 1
19
22U/35V 2
390K
Calibration
K
1
5
P1
R14
LED3
HT82V739
Driver
Related Data Report
Item
ESD test report
Operating current
JP1
1
2
3
4
5
PA2/A1P
3V3
VSS
RESET
PA0
R3
C10
104
10U /16V
750K
LED3
1K
13 PA7/A2E/BZB
C2
R13
Bat/Error
R2
14 PA6/A2N/BZ
9V
LED2
R9
W
D2 1N4148
Alarm
R1
2
PA3/A1N/INT0
10uF
3V3
LED1
Type
Result
CONTACT type
10kV no reset or system crash
AIR type
16kV no reset or system crash
Typ. standby current
22A
Max. standby current
28A
Alarm operating current
Less than 50mA