SNC342
Direct Drive Voice/Dual Tone Melody Controller
1
INTRODUCTION
SNC342 is a 1-channel voice synthesizer and dual-tone melody IC with PWM direct
drive circuit. It built-in a 4-bit tiny controller with one 4-bit input port and two 4-bit I/O
ports. By programming through the tiny controller in SNC342, user’s varied
applications including voice section combination, dual-tone melody, key trigger
arrangement, output control, and other logic functions can be easily implemented.
2
FEATURES
Single power supply 2.4V – 5.5V
16 seconds voice capacity are provided (@6KHZ sample rate)
Built in a 4-bit tiny controller
One 4-bit input port and two 4-bit I/O ports are provided
128*4 bits RAM are provided
52K*10 ROM size are provided for voice data and program
Maximum 16k program ROM is provided
Readable ROM code data
IR carrier signal is provided
Built in a high quality speech synthesizer
Adaptive playing speed from 2.5k-20kHz is provided
One voice channel plus Dual-Tone Melody
Built in a PWM Direct Drive circuit and a fixed current D/A output
System clock: 2MHz
Low Power Reset
Ver: 1.4
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June 8, 2005
SNC342
Direct Drive Voice/Dual Tone Melody Controller
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Block Diagram
ROM
Program/Speech
52K×10 bits
Address Pointers/ STACK
SRAM (128 nibbles)
Timer
ALU
IO1
Sampling
Rate Counter
Timing
Generator
Dual-Tone
Generator
OSC
PWM
D/A
IO3
Voice
Synthesizer
IO2
4
PIN ASSIGNMENT
Symbol
P13 ~ P10
P23 ~ P20
P33 ~ P30
VDD
GND
RST
OSC
BUO1/VO
BUO2
I/O
I
I/O
I/O
P
P
I
O
O
O
Function Description
Bit3 ~ Bit0 of Input port 1
Bit3 ~ Bit0 of I/O port 2
Bit3 ~ Bit0 of I/O port 3
Positive power supply
Negative power supply
Reset pin (active high)
Oscillator / Crystal Out
Positive Output of PWM or DA output
Negative Output of PWM
Ver: 1.4
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June 8, 2005
SNC342
Direct Drive Voice/Dual Tone Melody Controller
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FUNCTION DESCRIPTIONS
5.1. Oscillator
SNC342 accept RC type oscillator for system clock. The typical circuit diagram for
oscillator is listed as follow.
VCC
RC Oscillator
5.2. ROM
SNC342 contains substantial 52K words (10-bit) internal ROM. Program, voices and
other data are shared with this same 52K words ROM.
5.3. RAM
SNC342 contains 128 nibbles RAM. The 128 nibbles RAM are divided into eight
pages (page 0 to page 7, 16 nibbles RAM on each page). In our programming
structure, users can easily define and locate RAM page in the program. For instance,
users can use the instructions, PAGEn (n=0 to 7) to switch and indicate the RAM page.
Besides, users can use direct mode, M0 ~ M15 in the data transfer type instructions, to
access all 16 nibbles of each page.
5.4. Power Down Mode
“End” instruction will power down SNC342 and enable IC to consume fewer current for
power saving. (<3uA @VDD=3V and <5uA @VDD=5V) Please be aware that when
the power down mode is activated in SNC342, any valid data transition (L H or H L)
occurring on any input port (P1) or IO ports (P2 and P3) will lead SNC342 back to
normal operation mode.
5.5. Sampling Rate Counter
The unique sampling rate counter is designed in voice channel to be able to play
diverse voices at different sample playing rates. The playing rate can be adaptively
set up among from the wide ranges of 2.5KHz to 20KHz. This feature makes voice
close to its original source and yield the better voice quality.
Ver: 1.4
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June 8, 2005
OSC
SNC342
Direct Drive Voice/Dual Tone Melody Controller
5.6. Dual-Tone Generator
A dual-tone melody generator is included to generate 2-channel music songs with a
pleasant square-wave-like timbre. The pitch range of each tone generator is as wide
as 4 octaves (48 different notes totally). The output of dual-tone generator can be
mixed with the output of voice synthesizer to achieve voice playing with BGM
(background music). Additionally, Sonix provides a numbered-musical-notation
representation to help users compose their songs. Further, a MIDI (1.0) file translator
can convert MIDI files into Sonix format.
5.7. I/O Ports
P1 is a 4-bit input port and P2/P3 are two 4-bit I/O ports. Any bit of P2 and P3 can be
programmed as either input or output port individually. Any valid data transition (H L
or L H) of P1, P2 and P3 can reactivate the chip when the chip is in power-down
mode.
To Internal Data Bus
PAD
Read Control
Weak
Input Port Configuration (P10~P13)
Port Data
PAD
Port Status
Weak
To Internal Data Bus
Read Control
I/O Port Configuration (P20~P23, P30~P33)
Note: weak N-MOS’s can serve as pull-low resistor.
Ver: 1.4
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June 8, 2005
SNC342
Direct Drive Voice/Dual Tone Melody Controller
5.8. IR Function
P33 can be modulated with 38.5KHz square wave before sent out to P33 pin. The IR
signal can be achieved by this modulated signal.
38.5KHZ
"1"
PAD
Mode
P33
5.9. DAC & PWM
SNC342 is an advanced chip to be designed having two optimal methods to play out
the voices. One is DAC and the other is PWM. Upon user’s applications, user can
select either DAC or PWM in his design. Please be aware that only one method can
be activated at a time.
DAC:
A 7-bit current type digital-to-analog converter is built-in SNC342. The
relationship between input digital data and output analog current signal is listed in the
following table. Also, the recommended application circuit is illustrated as follows.
Input data
0
1
…
N
…
127
Typical value of output current (mA)
0
3/127
n*(3/127)
3
Ver: 1.4
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June 8, 2005
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