Holtek Semiconductor Inc HT818D0 Datasheet
22.4-Second LOG-PCM Speech
Features
Operating voltage: 3.6V~5.0V
·
Directly drives an external transistor
·
Low standby current (1mA typ. for VDD=3V)
·
Minimal external components
·
508 words table ROM for key functions
·
Programmable silence length and end-pulse
·
width (minimal end-pulse width is 330msata
6kHz sampling rate)
22.4-second voice capacity (based on a 6kHz
·
sampling rate)
Section options
·
-
Retriggerable
-
Non-retriggerable
FLAG1 options
·
-
End-pulse output
-
3HzB flash
-
6HzB flash
-
Voice output indication
-
Busy output
HT818D0
FLAG2 options
·
-
3Hz flash
-
6Hz flash
-
Busy output
Controllable volume
·
12 keys
·
Key options
·
-
Stop key: KEY12
-
Random (only for KEY1)
-
Sequential (only for KEY1)
-
Repeat (for all KEYs)
-
Key debounce time (for all KEYs): 700ms,
22ms, 45ms, 180ms (based on a 6kHz
sampling rate)
-
One shot (for all KEYs)
-
Level-trigger
-
Pull-high resistance (for all KEYs)
Dice form or 20/24-pin DIP/SOP package
·
Applications
Leisure products
·
Alarm clocks
·
Public address system
·
General Description
The HT818D0 is a single chip LOG-PCM voice
synthesizer LSI with 22.4-second voice capacity
at a 6kHz sampling rate. The chip when triggered drives a speaker through an external
transistor with a current switch D/A converter
output. Negligible current will be consumed in
the standby state.
The HT818D0 provides 12 key inputs and 2 pro
grammable FLAG outputs. With a 3.6V~5.0V
power supply, a complete synthesized voice
playback system can be easily built with very
few external components.
Alert and warning system
·
Sound effect generators
·
The customer¢s voice sources are recorded section by section into an internal mask ROM. The
sectional playback arrangement instructions of
each key are stored in the table ROM. The key
features are also programmable. With such a
flexible structure, the HT818D0 is excellent for
versatile voice applications.
-
1 March 15, 2000
Block Diagram
HT818D0
KEY1
KEY12
OSC1
OSC2
AUD
Pin Assignment
KEY7
KEY8
KEY9
KEY10
KEY11
KEY12
NC
VDD
AUD
OSC2
1
2
3
4
5
6
7
8
9
10
H T818D 0
20 DIP/SO P
20
19
18
17
16
15
14
13
12
11
KEY6
KEY5
KEY4
KEY3
KEY2
KEY1
FLAG 2
VSS
FLAG 1
OSC1
D ebounce
Circuit
O scillator
Circuit
DAC &
O utput
C ontrol
One-shot
Tim e Base
G enerator
Voice R O M
128K ´ 6 -b it
KEY7
KEY8
KEY9
KEY10
KEY11
KEY12
NC
VDD
AUD
OSC2
OSC1
FLAG 1
Key Table
Table R O M
508
R O M Address
C ounter
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
H T 8 1 8 D 0
24 DIP/SO P
14-bit
´
KEY6
KEY5
KEY4
KEY3
KEY2
KEY1
NC
NC
NC
NC
FLAG 2
VSS
Status
Display
C ontroller
VDD
VSS
FLAG 1
FLAG 2
2 March 15, 2000
HT818D0
Pad Assignment Pad Coordinates
KEY10
KEY11
KEY12
KEY9
1
19
2
3
4
VDD
5156
AUD
KEY8
KEY7
KEY6
KEY5
Pad No. X Y
14
16717818
KEY4
13
KEY3
12
KEY2
11
KEY1
1
2
3
4
5
6
-914.50
-914.50
-914.50
-987.90 -2023.45
-254.60 -1996.95
-18.90 -1996.95
7 411.90
8 674.70
9 806.10
(0 ,0 )
10 937.90
11 912.80 1501.15
12 912.80 1639.75
13 912.80 1835.15
14 912.80 1978.75
15 709.50 1949.25
16 179.20 1949.25
17 22.00 1949.25
18
19
10
OSC2
9
OSC1
FLAG 1
VSS
FLAG 2
-156.40
-734.20
Unit: mm
1997.95
1854.55
1663.95
-1996.95
-1996.95
-2027.55
-1996.95
1949.25
1949.25
Chip size: 2270 ´ 4400 (mm)
2
* The IC substrate should be connected to VSS in the PCB layout artwork.
Pad Description
Pad No. Pad Name I/O
1~3 KEY10~KEY12 I Pull-high
4 VDD
5 AUD O
6 OSC2 O
7 OSC1 I
Internal
Connection
¾¾
PMOS
Open Drain
¾
¾
3 March 15, 2000
Description
Trigger key, low active. Key features such as
debounce time, pull-high resistance and repeat
are all by mask option.
Positive power supply
Voice output for driving an external transistor
Oscillator output pin
Oscillator input pin
HT818D0
Pad No. Pad Name I/O
8 FLAG1 O
9 VSS
10 FLAG2 O
Internal
Connection
NMOS
Open Drain
¾¾
NMOS
Open Drain
Description
3HzB/6HzB flash output, busy output,
end-pulse or voice output indication (by mask
option). Open drain, active low output.
Negative power supply, ground
3Hz/6Hz flash output or busy output (by mask
option). Open drain, active low output.
Trigger key, low active. Key features such as
11~19 KEY1~KEY9 I Pull-high
debounce time, pull-high resistance and repeat
are all by mask option.
Absolute Maximum Ratings
Supply Voltage ................................-0.3V to 6V
Input Voltage .................V
-0.3V to VDD+0.3V
SS
Note: These are stress ratings only. Stresses exceeding the range specified under ²Absolute Maxi
mum Ratings² may cause substantial damage to the device. Functional operation of this de
vice at other conditions beyond those listed in the specification is not implied and prolonged
exposure to extreme conditions may affect device reliability.
Electrical Characteristics
Storage Temperature ................-50°Cto125°C
Operating Temperature .............-20°Cto70°C
Ta=25°C
-
-
Symbol Parameter
V
I
I
I
I
V
V
DD
STB
O
OL
f
OSC
DD
IH
IL
Operating Voltage
Operating Current 3V No load
Standby Current 3V
Max. AUD Output Current 3V
FLAG Sink Current 3V
²H² Input Voltage ¾¾
²L² Input Voltage ¾¾
Oscillating Frequency 3V
Test Conditions
DD
Conditions
V
¾¾
¾¾
V
=0.6V
OH
V
=0.3V
OL
=530kW
R
OSC
4 March 15, 2000
Min. Typ. Max. Unit
3.6
¾
¾
200 400
5.0 V
13
-1.5 -2 ¾
1.5 3.0
0.8V
0
DD
¾
¾
¾
V
0.2V
DD
mA
mA
DD
76 96 116 kHz
mA
mA
V
V
Functional Description
The HT818D0 is a mask ROM type voice synthe
sizer with 22.4-second voice capacity. A group of
pre-recorded voice sections is played upon receipt
of key trigger input signals. Two FLAG signals
are output while playing voices.
The 22.4-second voice capacity can be divided
into sections of arbitrary length. Notice that the
silence length and end-pulse width are not in
cluded in the memory.
By using Holtek¢s programming tools, the con
tents and arrangement of sections, as well as
key features and FLAG output are all program
mable before device fabrication.
The IC provides 12 key inputs (KEY1~KEY12).
Of the 12 keys, KEY1 can be optioned as a di
rect, sequential or random trigger key. KEY12
can be selected as a stop or direct key. The re
maining 10 keys (KEY2~KEY11) are used as di
rect keys exclusively.
Play function block diagram
V
DD
Key
trigger
Key
features
option
Playing control logic
System oscillator
The HT818D0 has a built-in RC oscillator
which requires only one external resistor for
normal applications. The oscillator frequency
is typically 96kHz for an external resistor of
530kW. The required oscillator frequency may
vary with different sampling rates in the pro
cess of voice programming. As a result, the
value of the oscillator resistor may be differ
ent for different items.
Key
fu n c tio n
ta b le
ROM
OSC1
H T818D 0
OSC2
Voice
ROM
R
OSC
D/A
Flag
output
The oscillator is turned on when triggered by a
key input. After playing, it is immediately turned
off and the chip goes into the standby state.
Voice ROM
The voice ROM is originally designed to continu
ously record the 22.4-second voice data at a 6kHz
sampling rate. Ahigher sampling rate can gener
ate voices of better playback quality, but will
shorten the total recording time. On the other
hand, a lower sampling rate results in longer re
cording time but sacrifice voice quality.
The playback time can be significantly extended
by making use of coding efficiency, silence play
ing, section repeating, section cascade, etc.
-
Section
Section is the basic element constituting the
contents of voice ROM. During programming,
the customer¢s voice sources can be divided into
as many sections as required. A section can be
composed of a voice or an interval of silence.
However, the silence length is not counted in
the voice ROM. The total number of sections included should be less than 508 due to the space
limitation of the function table ROM. The total
length of the included sections is limited by the
voice ROM.
A section, when triggered by a key input, can be
played once, repeatedly or cascaded with other
sections, depending on the key function table
instructions.
The following are examples of section division:
Exam ple 1: O ne section only
sec.1
ROM
Exam ple 2: 3 section division
-
sec.1 sec.2 sec.3
-
Exam ple 3: N section division
sec.2 sec.Nsec.1
ROM
ROM
HT818D0
-
-
-
-
5 March 15, 2000
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