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.
1 5th May ’98
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
2 5th May ’98
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
3 5th May ’98
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.
4 5th May ’98
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
5 5th May ’98
HT812D0
As stated on the table, KEY1 can be made up
of sub-groups. The corresponding sub-groups
is played in sequence each time KEY1 is triggered.
♦
The playing sequence of sequential KEY1 is:
Group 1-1
→ Group 1-2 → Group 1-3 ..... →
Group 1-N (the last group) → Group 1-1 .....
♦
The playing sequence of random KEY1 is:
Group 1-3
→ Group 1-5 ..... → Group 1-N →
Group 1-3 → Group 1-5 .....
That KEY1 functions as a random key is a
special case of sequential key , which combines
a particular arrangement of sub-group playing sequence.
♦
Reset of KEY1 playing sequence
If a sub-group of KEY1 group is being played
and one of the keys from KEY2~KEY4 is
triggered, the playing sub-group will be terminated, and the newly triggered key group
is played instead. The first sub-group will
start playing by retriggering KEY1. In other
words, the KEY1 playing sequence is reset
whenever a key other than KEY1 is triggered (see Figure 1).
♦
Sub-group selection
When KEY1 is triggered with pulses, the desired sub-group can be selected by controlling
its corresponding pulse number.
The features o f KEY1 h ave to b e set in th e
following ways:
–
sequential or random
–
retriggerable
–
minimum key debounce time
(
≅700µs, f
OSC
=96kHz)
For instance, if sub-group 1-3 is the previous
playing group, sub-group 1-5 will start playing
after 2 pulses are appli ed to KEY1, an d so on.
To make easy selection of KEY1 sub-groups,
one of KEY2~KEY4 should be programmed as
silence. Then this silence key has to be triggered to reset KEY1. By so doing, the playing
sub-group of KEY1 is directly specified by the
pulse number applied to KEY1 (see Figure 2).
•
KEY4 as a stop key (by mask option)
When KEY4 functions as a stop key , any voice
output can be stopped by pressing KEY4.
•
KEY1~KEY3 as a repeat key
KEY1~KEY3 all functi on as repeat key if one
of the three keys is set as a repeat key. In
other words, once the mode of one of
KEY1~KEY3 is determined, the remaining
two keys are set accordingly.
As a repeat ke y, the sections incl uded ca n be
played sequentially and repeatedly till other
trigger is applied. KEY4 functio ns as a stop
key when KEY1~KEY3 are set as repeat
keys.
Figure 1 Reset of KEY1 playing sequence
Figure 2 KEY1 sub-group selection
6 5th May ’98
When KEY1~KEY3 are set as repeat keys, the
key function should be option ed as retrigge rable keys.
Key features
•
Key priority
When two or more keys are triggered simulta-
neously, the output v oice is de cided by t he key
priority as shown below:
KEY1>KEY2>KEY3>KEY4
•
Key debounce time
There are four kinds of key-in deboun ce time to
be selected by mask option, namely , 700
µs, 22ms,
45ms and 180ms. The k ey de boun ce tim e var i es
with the value of the system frequency.
•
Pull-high resistance
Four kinds of key inp ut pin pu ll -hig h resis-
tance can be selected by mask option,
namely, 20k
Ω, 50kΩ, 100kΩ and 200kΩ.
The resistance may vary with VDD, temperatures and the chip itself due to process
variations.
•
Trigger mode
All of the four keys can be optioned as one-
shot trigger mode or level-trigger mode.
♦
One shot
When one of the four keys (KEY1~KEY4) is
pressed and held down, the group corresponding to that held key will play once. The
corresponding group will also play once
when one of the four keys is pressed momentarily .
HT812D0
FLAG
When voices are playing, both FLAG1 and
FLAG2 pins are activated to output one of the
following signals through code option.
FLAG1 can be o ptione d as on e of the fo llowing
signal outputs:
None, 3Hz flash, Busy, 6Hz flash, Voice indicator,
or End-pulse output
FLAG2, on the other hand, can be set as one of
the following signal ou tputs:
None, 3Hz flash, 6Hz flash, or Busy output
•
3Hz flash
When voices are playing, FLAG1 as well as
FLAG2 pin outputs a 3 Hz signal to drive a n
LED. The signal is active low, 25% duty. Once
the voice output is terminated, FLAG1 and
FLAG2 pins b ecome floating outputs. When
FLAG1 and FLAG2 pins are optioned as 3Hz
output, they will be al ternately sign aled at a
3Hz rate output.
♦
Level trigger
When one of the four keys is pressed and
held down, the corresponding group will
keep playing. Once the pressed key is released, the group will not stop till the included sections are all completed.
•
6Hz flash
When voices are playing, the FLAG1 pin
outputs a 6Hz signal to drive an LED. The
signal is active low , 25% duty . Once the voice
output is terminated, the FLAG1 pin becomes a floating output. When the FLAG1
and the FLAG2 pins are optioned as 6Hz output, they will be alternately signaled at a 6Hz
rate output.
7 5th May ’98
•
Busy output
When a voice group is playi ng, the ou tputs of
both FLAG1 and FLAG2 are turned low , indicating that the chip is busy.
In addition to the above-stated output signals,
FLAG1 can also generate one of the following
signals by code option:
•
Voice indicator output
FLAG1 is active low when voices are playing.
It is also turned low during a voice section
output. FLAG1 becom es a floating outp ut after the silence secti on o utput is com pleted or
the voice output is terminated.
HT812D0
•
End-pulse output
When the voice output is completed, the
FLAG1 pin outp uts an active low pulse. The
pulse width can be programmed depending on
the customer’s requirements.
FLAG1 and FLAG2 pins are both floating
outputs when the chip is in the standby state.
Volume control
The function of the volume control can be set by
mask option. A code is written in th e function
table for the purp ose of contro lling the vol ume
of each section output after the volum e control
function is chosen. There are two volume options, namely, full range and half range.
AUD
The AUD pi n is a PM OS op en dra in stru cture.
It outputs voice signals to drive a speaker
through an external NPN transistor when the
chip is active. However, the AUD pin becomes a
floating output when the chip is in the standby
state.
The 8050 type trans istor with h
ommended for an output driver.
≅150 is rec-
FE
8 5th May ’98
Timing Diagram
One-key operation
•
Sequential-retriggerabl e
•
Sequential-nonre triggerable
•
Random-retriggerable
HT812D0
•
Random-nonretriggerable
Note: Group 1-N may be any of the KEY1 groups
9 5th May ’98
Multi-key operation
•
Retriggerable
•
Non-retriggerable
HT812D0
•
Repeat
Note: M, N=1:4
10 5th May ’98
Application Circuits
General application
Parallel application
HT812D0
11 5th May ’98
Cascade or external driving
Power- on play (one shot)
HT812D0
12 5th May ’98
Power-on play (continuous)
With volume adjustment
HT812D0
13 5th May ’98
HT812D0
Push-pull output
To prevent the speaker and driver tra nsistor from damage due to exces s power dissipation which
results from a high voltage power supply (4.5V~5.5V), the following push-pull output stage is
recommended.
Coupling to power amplifier
14 5th May ’98
Standard Item List
HT812D0
Item Name R
HT812D1
HT812D2
HT812D3
HT812D4
HT812D5
HT812D6*
HT812D7
HT812D8
HT812D9
HT812DD
HT812DF*
HT812DG
HT812DH
HT812DJ
HT812DK
HT812DL
HT812DN*
Baby Cry
Firecracker
Train Sound (I)
Crazy Laugh
Witch Laugh
Glass Broken
Scream Sound
Racing Car Sound
Truck Sound
Duck
Monkey
Horse
Cat
Lion
Elephant
Sheep
Train Sound (II)
OSC
Remarks
532kΩ 4 keys
370k
Ω 4 keys
Ω 4 keys
570k
787k
Ω 4 keys
Ω 4 keys
469k
— 4 keys
419k
Ω 4 keys
Ω 4 keys
572k
450k
Ω 4 keys
397k
Ω 4 keys
— 4 keys
570k
Ω 4 keys
Ω 4 keys
427k
472k
Ω 4 keys
363k
Ω 4 keys
Ω 4 keys
264k
— 4 keys
* Under development
15 5th May ’98
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