®
®
IS22C040
IS22C040
32 to 40 SEC INSTANT VOICE ROM
ISSI
ISSI
OCTOBER 1998
FEATURES
GENERAL DESCRIPTION
• Voice length at
IS22C040isahigh-qualityvoicesynthesizerwithacapacity
of 32 to 40 seconds. A proprietary ADPCM algorithm is
used. The audio message is stored in a 1024-Kbit on-chip
EPROM.
– 8 KHz sampling is 32 seconds
– 6 KHz sampling is 40 seconds
• Silence compression to save memory
• Eight trigger pins, S1 to S8 for 32 sections
• SBT pin play-all or sequential play-all
• 15 ms debounce time suitable for CDS
• IRP interrupt pin stops playback at once
• STP stop pulse generated at end of playback
• BUSY signal for CPU control
TheIS22C040eliminatestheneedofcomplicatedcircuitry
in voice playback (Figure 1) but still achieves high voice
quality. Sounds such as human speech, animal sounds,
musical sounds, and even special sound effects can be
synthesized. Devices can be cascaded to achieve longer
voice duration (Figure 3). Two devices can be configured
in parallel (Figure 4) in order to achieve signal mixing
without an external mixer allowing speeches to be mixed
with background music synthesis from two different chips.
• Two LEDs flash at 3 Hz interval
The instant programming nature of the IS22C040 allows a
very short production turnaround time. There are no NRE
charges that are usually required with conventional voice
ROMs. Users now can apply a voice synthesis function as
anadditionalfeaturetotheirproductsevenwhenproduction
volume is relatively small. It is also ideal for trial or
engineering prototyping. As a result, the initial investment
is minimal and the risk in the product development phase
is reduced.
• 3.0V to 6V single power supply operation
• Low standby current (<5 µA at 3V)
• Auto-power down
• Built-in oscillator, D/A converter, EPROM
• ADPCM data compression
• Optional pop noise elimination function
• COUT pin drives speaker with a transistor
• Development tools support
The IS22C040 provides a wide voltage operating range
from 3.0V to 6.0V. A pair of PWM output pins, VOUT1 and
VOUT2 provide direct drive to a buzzer (Figure 2). Voice
quality from a buzzer is comparable to speaker output and
power consumption is much lower.
• VOUT1 and VOUT2 drives buzzer directly
• Sampling rate determined by external resistor
• Holdable and unholdable triggering option
• Industrial temperature available
A current output pin, COUT, enables the device to drive a
speaker with a low cost NPN transistor. No complex
filtering or amplifier circuit is needed. An automatic ramp
up/down function eliminates the undesired noise at the
end of playback.
Up to 32 sections are accessible through S1 to S8. The
SBT trigger pin can be programmed to playback all 32
sections or sequentially from section 1 to 32. An interrupt
pin (IRP) and stop pulse (STP) or BUSY signals provide
handshaking with microprocessors or other IS22C040
devices. All trigger pins give 15 ms debounce time and is
ideal for CDS applications as in Figure 6. Two LED drivers
are available, flashing on and off at approximately 3Hz
intervals (Figure 5). The internal voltage compensation
oscillator requires only one external resistor. Different
sampling frequencies are determined by the external
oscillator resistor value.
ISSI reserves the right to make changes to its products at any time without notice in order to improve design and supply the best possible product. We assume no responsibility for any errors which
may appear in this publication. © Copyright 1998, Integrated Silicon Solution, Inc.
Integrated Silicon Solution, Inc.
VP009-1C
10/01/98
1
ISSI [ INTEGRATED SILICON SOLUTION, INC ]
