Holtek Semiconductor Inc HT812D0 Datasheet
2.8 Second LOG-PCM Speech
Features
•
Operating voltage: 2.4V ~5.0V
•
Directly drives an external transistor
•
Low standby c urr en t ( 1µ A Ty p. f o r VD D = 3V)
•
Minimal external components
•
124 words table ROM for key functions
•
Programmable silence length and end-pulse
width (minimal end-pulse width is 330
6kHz sampling rate)
•
2.8-second voice capacity
•
Controllable volume
•
FLAG1 options:
–
End-puls e output
–
3Hz flash
–
6Hz flash
–
Voice output indication
–
Busy output
•
FLAG2 options:
–
3Hz flash
–
6Hz flash
–
Busy output
µs at a
HT812D0
•
Four keys
•
Key options:
–
Stop key: KEY4
–
Random (only for KEY1)
–
Sequential (only for KEY1)
–
Repeat (for all KEYs, under retriggerable
condition)
–
Key debounce time (for all KEYs): 700µs,
22ms, 45ms, 180ms (based on a sampling
rate of approximately 6kHz)
–
One shot (for al l KEYs )
–
Level-trigger
–
Pull-high resistance (for all KEYs)
•
Section options:
–
Retriggerable
–
Non-retriggerable
Applic a tions
•
Toys
•
Alarm clocks
•
Public address system
General Description
The HT812D0 is a single chip LOG-PCM voice
synthesizer LSI wi th 2.8-second voice capacity
at 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 HT812D0 provides four key inputs and two
programmable FLAG outputs. With a 2.4V~5.0V
power supply, a complete synthesized voice
playback system can be ea sily built with very
few external components.
•
Alert & warning system
•
Sound effect generators
The custome r’s voice s ources are reco rded 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 HT812D0 is excellent for
versatile voice applications.
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Pin Assignment Block Diagram
HT812D0
Pad Assignment
Pad No. X Y
1 –919.00 480.30
2 –1007.00 –530.30
3 –226.99 –480.30
4 61.70 –480.30
5 515.20 –480.30
6 821.90 –480.30
7 1006.90 –530.30
8 957.00 289.10
9 894.20 480.30
10 –291.90 480.30
11 –532.50 480.30
Chip size: 2270
* The IC substrate should be connected to VSS in the PCB layout artwork.
× 1380 (µm)
2
Pin Description
Pin No. Pin Name I/O
1 OSC1 I — Oscillator input pin
2 FLAG1 O
3 VSS I — Negative power supply (GND)
4 FLAG2 O
Internal
Connection
NMOS
Open Drain
NMOS
Open Drain
Description
3Hz/6Hz flash output, busy output, end-pulse or
voice output indication (by mask option). Open
drain, active low output
3Hz/6Hz flash output or busy output (by mask
option), open drain, active low output
Unit: µm
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HT812D0
Pin No. Pin Name I/O
Internal
Connection
Description
Trigger key, active low. Key features like
5~8 KEY1~ KEY4 I Pull-High
debounce time, pull-high resistance and repeat
can be selected by mask option.
9~13 NC — — No connection
14 VDD I — Positive power supply
15 AUD O
PMOS
Open Drain
Voice output for driving an external transistor
16 OSC2 O — Oscillator output pin
Absolu te Maxim um Ratings *
Supply Voltage ............................... –0.3V to 6V Storage Temperature ............... –50°C to 125°C
Input Voltage ............... V
–0.3V to VDD+0.3V Operating Temperature ............. –20°C to 70°C
SS
*Note: These are stress ra tings on ly. Stresses exceeding the range spe cified un der “Abso lute Maxi-
mum Ratings” ma y cause substantial damage to the device. Functional operation of this
device at other conditions beyond those listed in the specification is not implied and prolonged
exposure to extreme condition s may affect device reliability.
Electrical Cha racteristics (Ta=25°C)
Symbol Parameter
V
I
DD
I
STB
I
O
I
OL
V
V
f
OSC
Operating Voltage — — 2.4 — 5.0 V
DD
Operating Current 3V
Standby Current 3V — — 1 3 µA
Max. AUD Output Current 3V VOH=0.6V –1.5 –2 — mA
FLAG Sink Current 3V VOL=0.3V 1.5 3.0 — mA
“H” Input Voltage — — 0.8V
IH
“L” Input Voltage — — 0 — 0.2V
IL
Oscillati ng Frequency 3V R
Test Conditions
V
DD
Conditions
No load,
f
=96kHz
OSC
=570kΩ 60 76 92 kHz
OSC
Min. Typ. Max. Unit
DD
µA
V
—200400
—VDDV
DD
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Functional Description
The HT812D0 is a mask ROM type voice synthesizer with 2 .8-second voice capacity. A group of
pre-recorded voice sections is played upon receipt
of key trigger inpu t signals. Two output FLAGs
send signals while playing voices.
The 2.8-second voice capacity can be divided into
sections of arbitrary length. Notice that the silence length and end-pulse width are not included in the memory.
By using HOLTEK’s programming tools, the
contents and arrange ment of section s, key features and FL AG output are all programmable
before device fabrication.
The IC provides four key inputs (KEY1~KEY4).
Of the four keys, KEY 1 can be optioned as a
direct, sequential or random trigger key. KEY4
can be selected as a stop or direct key. The
remaining two keys (KEY2, KEY3), are used as
direct keys exclusively.
System oscillator
The HT812D0 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
530k
Ω. The required oscillator frequency m ay
vary with different sampl ing rates in the pro cess of voice programming. As a result the value
of the oscillator resistor may be different for
different items.
The oscillator is turned on when triggered by a
key input. After playing, the oscillator is immediately turned off and the chip goes into the st andby
state.
HT812D0
Play function block diagram
Voice ROM
The voice ROM is originally designed to continuously record the 2.8-second voice data at about
6kHz sampling rate. A higher sampling rate can
generate voices of good playback quality, but will
shorten the total recording time. On the other
hand, a lower sampling rate will result in longer
recording time but sacrifice voice quality.
The playback time can be significantly ex tended
by making use of coding efficiency, silence playing,
section repeating, section cascade, et c.
Section
Section is the basic element constituting the
contents of the voice ROM. During programming, the custome r’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 silent length is not
counted in the voice ROM. The total nu mber of
sections included should be less than 124 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.
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HT812D0
The following are examples of section division:
In addition, a section can be set as retriggerable
or non-retriggerable de pend ing on the code option.
•
Retriggerable
When the currently p laying section is set as
retriggerable, it will stop im mediately upon
receipt of other key inputs.
•
Non-retriggerable
When the currently playing section is selected
as non-retriggerable, it will keep on playing till
the whole section is completed, whether or not
there is a key input during voice playing.
For a key group, some sections can be set as
retriggerable and some as non-retrigge rable.
When a retriggerable section of a key group is
playing, any key can be triggered to interrupt
its playing. On the other hand, if a non-retriggerable sectio n is playing, any key inte rrupt
is invalid.
Group
The HT812D0 plays groups according to the key
input. A group can be made up of on e or more
sections. When a key is triggered, the corresponding group is played immediately. For example, triggering KEY2 plays group 2, and so
on. The same section is allowed to appear in
different groups. However, KEY1 can be made
up of multiple grou ps when it is op tioned as a
sequential or ra ndo m key. Otherwise, each key
is composed of one group only.
Key function table
Sections in the voice ROM are played according
to the instructions of the key function table. The
function table contains grou p information and
the playing order of section s in the grou ps. No tice that the tota l amount of sectio ns included
in the groups should be less than 124–the space
limitation of the function table ROM.
•
KEY1 as a direct key
Each key is mapped to a group in the function
table. If a key is not used, the group mapped
to that key is a piece o f sil ence. The following
is an example of the function table:
Group 1 sec.1 + sec.2 + sec.3 + sec.5
Group 2 sec.3
Group 3 sec.2 + sec.2 + sec.3 + sec.4
Group 4 sec.5 + sec.3
As illustrated on the above table, the voice
ROM is composed of 5 sections, and as a whole
comprise 11 sections for the function tabl e. If
KEY1 is momentarily triggered, section 1,
section 2, section 3 and section 5 are played in
sequence and then stopped. Triggering KEY2
plays section 3, and so on.
•
KEY1 as a sequen tial or random ke y
When KEY1 is optioned as a sequential or
random key, KEY1 can include multiple
groups (sub-groups) in the function table.
However , the remaining 3 keys ( KEY2~KEY4)
are used as direct keys exclusively and comprise only one group in the function table.
An example is show n below:
Group 1-1 sec.4 + sec.2
Group 1-2 sec.1 + sec.3
:
:
:
:
Group 1-N sec.2 + sec.3
Group 2 sec.2 + sec.3
Group 3 sec.3 + sec.5
Group 4 sec.1 + sec.5 + sec.2
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