SNC374
Direct Drive Voice/Dual Tone Melody Controller
1
INTRODUCTION
SNC374 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 three 4-bit I/O
ports. By programming through the tiny controller in SNC374, 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
42 seconds voice capacity are provided (@6KHZ sample rate)
Built in a 4-bit tiny controller
One 4-bit input port and three 4-bit I/O ports are provided
128*4 bits RAM are provided
132K*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: 1.2
1
December 26, 2002
SNC374
Direct Drive Voice/Dual Tone Melody Controller
3
Block Diagram
ROM
Program/Speech
132K×10 bits
Address Pointers/ STACK
SRAM (128 nibbles)
Timer
ALU
IO1
IO2
Sampling
Rate Counter
Timing
Generator
Dual-Tone
Generator
OSC
PWM
D/A
IO6
Voice
Synthesizer
IO3
4
PIN ASSIGNMENT
Symbol
P13 ~ P10
P23 ~ P20
P33 ~ P30
P63 ~ P60
VDD
GND
RST
OSC
BUO1/VO
BUO2
I/O
I
I/O
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
Bit3 ~ Bit0 of I/O port 6
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: 1.2
2
December 26, 2002
SNC374
Direct Drive Voice/Dual Tone Melody Controller
5
FUNCTION DESCRIPTIONS
5.1. Oscillator
SNC374 accept RC type oscillator for system clock. The typical circuit diagram for
oscillator is listed as follow.
VCC
RC Oscillator
5.2. ROM
SNC374 contains substantial 132K words (10-bit) internal ROM. Program, voices and
other data are shared with this same 132K words ROM.
5.3. RAM
SNC374 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 SNC374 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 SNC374, any valid data transition (L H or H L)
occurring on any input port (P1) or IO ports (P2, P3 and P6) will lead SNC374 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: 1.2
3
r
December 26, 2002
OSC
SNC374
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/P6 are three 4-bit I/O ports. Any bit of P2, P3 and P6
can be programmed as either input or output port individually. Any valid data transition
(H L or L H) of P1, P2, P3 and P6 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, P60~P63)
Note: weak N-MOS’s can serve as pull-low resistor.
4
Ver: 1.2
December 26, 2002
SNC374
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
SNC374 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 SNC374. 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: 1.2
5
December 26, 2002
Microchip MCU
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