HOLTEK HT1612

HT1612
Timer with Dialer Interface
Features
•
•
•
•
•
•
Operating voltage: 1.2V~1.7V
Dialing number and conversation time display
Conversation timer (Max. to 59 mins and 59
secs)
Operation current: 10µA (Typ.)
•
32768Hz crystal
8 or 10 digits LCD display driver, 3V, 1/2
bias, 1/3 duty (8 digits hand-held calculator
LCD is used for 8 digits application)
Built-in dialer interface
•
•
Telephone display interface
Instrument display
Applications
•
•
Timers
LCD display drivers
General Description
phone call, the HT1612 receives dialing data
from the dialer and displays the phone number
from left to right on the LCD. However, if there
is no dialing action within 10 seconds, it restarts the timer again. By adding a TIMER key,
the HT1612 can provide the timer reset/hold
functions (refer to functional description for
more details).
The HT1612 is a CMOS chip designed for dialer
interface which drives 8 or 10 digits LCD. Various functions, such as displaying dialing number and conversation time, are provided.
It normally shows blanks. The timer is started
to tell users how long the conversation time has
been taken when answering a telephone call.
After hanging up the telephone, it returns to
show blanks immediately. Whenever makeing a
1
5th July ’95
HT1612
Block Diagram
Pad Assignment
Chip size: 136 × 134 (mil)2
* The IC substrate should be connected to VDD in the PCB layout artwork.
2
5th July ’95
HT1612
Pad Coordinates
Pad No.
X
Unit: mil
Y
Pad No.
X
Y
Pad No.
X
Y
1
–61.92
41.65
18
–18.66
–60.80
35
61.63
39.46
2
–61.92
33.98
19
4.72
–60.80
36
61.63
47.60
3
–61.92
26.30
20
12.36
–60.80
37
61.63
55.79
4
–61.92
17.85
21
20
–60.80
38
41.78
61.14
5
–61.92
10.95
22
34.98
–60.46
39
33.62
61.14
6
–61.92
3.17
23
50.02
–60.46
40
25.46
61.14
7
–61.92
–4.53
24
61.67
–60.80
41
17.30
61.14
8
–61.92
–12.22
25
61.63
–42.18
42
9.14
61.14
9
–61.92
–19.96
26
61.63
–33.98
43
0.98
61.14
10
–61.92
–27.60
27
61.63
–25.82
44
–7.18
61.14
11
–61.92
–35.26
28
61.63
–17.66
45
–15.34
61.14
12
–61.92
–42.95
29
61.63
–9.50
46
–23.50
61.14
13
–61.92
–52.26
38
61.63
–1.34
47
–31.66
61.14
14
–57.80
–60.80
39
61.63
6.80
48
–39.82
61.14
15
–45.90
–60.80
31
61.63
14.98
49
–47.98
61.14
16
–36.50
–60.80
32
61.63
23.14
50
–56.14
61.14
17
–28.86
–60.80
33
61.63
31.30
Pad Description
Pad Name
I/O
Internal
Connection
SEG1~SEG30
O
CMOS OUT
LCD segement signal output pads
COM1~COM3
O
CMOS OUT
LCD common signal output pads
HK
I
CMOS IN
Pull-High
X2
O
OSCILLATOR 32768Hz crystal oscillator output
X1
I
OSCILLATOR 32768Hz crystal oscillator input
T2
I
CMOS IN
Pull-High
Test pad (connected to VSS for production test)
T1
I
CMOS IN
Pull-High
Test pad (connected to VSS for production test)
INT
O
NMOS OUT
TIMER
I
CMOS IN
Pull-Low
Description
Hook switch detector input
Active low
Interrupt output, 8 or 16Hz by mask option
Timer reset and start/hold toggle control input pad
3
5th July ’95
HT1612
I/O
Internal
Connection
DI
I
CMOS IN
Pull-High
Serial data input pad (connected to the dialer)
Data should be valid at the falling edge of SK
SK
I
CMOS IN
Pull-High
Clock input pad (connected to the dialer)
VSS
I
—
VA
O
CMOS OUT
Voltage doubler, connected to the external capacitor
VB
O
CMOS OUT
Voltage doubler, connected to the external capacitor
VC
O
CMOS OUT
Voltage doubler, connected to the external capacitor
VDD
I
—
Positive power supply
NC
—
—
No connection
Pad Name
Description
Negative power supply (GND)
Approximate internal connection circuit
Absolute Maximum Rantings
Supply Voltage ............................... –0.3V to 5V
Storage Temperature ............... –50°C to 125°C
Input Voltage ..................... VSS–0.3 to VDD+0.3
Operating Temperature ............. –20°C to 75°C
4
5th July ’95
HT1612
(FOSC=32768Hz, Ta=25°C)
Electrical Characteristics
Symbol
Test Condition
Parameter
VDD
Condition
Min.
Typ.
Max.
Unit
VDD
Operating Voltage
—
—
1.2
1.5
1.7
V
VIL
Input Low Voltage
1.2V~1.7V
—
VSS
—
0.2VDD
V
VIL
Input High Voltage
1.2V~1.7V
—
0.8VDD
—
VDD
V
ISTB
Stand-by Current
1.5V
VHK=Floating
(or VDD)
—
0.1
1
µA
IDD
Operating Current
1.5V
No load
—
10
30
µA
IOL
Output Sink Current of
INT
1.5V
VO=0.3V
500
1000
—
µA
TA
Data Setup Time
1.5V
—
1
—
—
µs
TB
Data Hold On Time
1.5V
—
2
—
—
µs
TC
Inter Digit Time
1.5V
—
5
—
—
µs
TDB
Debounce Time
(HK, TMIER)
1.5V
—
—
31.25
–
ms
RHI
Pull-High Resistance
(HK , DI, SK)
1.5V
VIN=0V
—
1
—
MΩ
RLO
Pull-Low Resistance
(TIMER)
1.5V
VTIMER=1.5V
—
5
—
MΩ
FOSC
System Frequency
1.5V
Crystal=32768Hz
—
32768
—
Hz
5
5th July ’95
HT1612
Functional Description
Operational flow chart
6
5th July ’95
HT1612
About On-Hook & Off-Hook
Note: 1. Figure a displays blanks.
2. Figure b illustrates a timer mode caused by Off-Hook; timer is reset and starts to
count the conversation time.
3. In Figure c. The dialing data are received and displayed on the LCD from left to right
after Off-Hook. When the entry interval is over 10 seconds, it resets the timer and starts
to count.
7
5th July ’95
HT1612
TIMER key function
In the conversation timer mode, the TIMER key can reset or hold the timer.
Data & Timing
• Data latch timing
• For instrument or µC application
The HT1612 is also capable of displaying the BCD data which are generated from instruments or
µC system. The corresponding data and timing are shown in Data latch timing. Before the data are
transmitted to the HT1612, the HK pin should be pull-low or keeps low always. Then, the HT1612
is ready to receive the data. At the falling edge of the clock the data are shifted to the IC. After the
whole data are sent to the HT1612, the SK pin is set low to avoid switching to the timer mode.
8
5th July ’95
HT1612
• For telephone application
The HT1612 is designed to display telephone numbers which are derived from the HT92XXX series
telephone dialers. The corresponding data are illustrated in the following table.
9
5th July ’95
HT1612
Application Circuits
For telephone interfacing
∗ The IC substrate should be connected to VDD in the PCB layout artwork.
10
5th July ’95
HT1612
For instrument or µC use (1.5V supply)
∗ The IC substrate should be connected to VDD in the PCB layout artwork.
Note:
1. To drive the SK, DI, and HK pin, an open drain NMOS output structure is recommended.
2. To drive the SK, DI and HK pin with CMOS output structure, a voltage divider is needed
(R=4.3K, R1=10K).
11
5th July ’95
HT1612
For insturment or µC use (3V supply)
∗ The IC substrate should be connected to VDD in the PCB layout artwork.
Note:
1. To drive the SK, DI, and HK pin, an open drain NMOS output structure is recommended.
2. To drive the SK, DI and HK pin with CMOS output structure, a voltage divider is needed
(R=20K, R1=10K).
12
5th July ’95
HT1612
LCD Connection
For 8-digit application
Segment Electrode Side
LCD driving system 1/2 bias, 1/3 duty, 3V.
Common Electrode Side
13
5th July ’95
HT1612
LCD Connection
For 10-digit application
Segment Electrode Side
* LCD driving system 1/2 bias, 1/3 duty, 3V.
Common Electrode Side
14
5th July ’95