SNC538
Two Channel Direct Drive Speech Controller
1 INTRODUCTION
SNC538 is a two-channel voice synthesizer IC with PWM direct drive circuit. It
built-in a 4-bit tiny controller with one 4-bit input port, two 4-bit output ports and three
4-bit I/O ports. By programming through the tiny controller in SNC538, user's varied
applications including voice section combination, key trigger arrangement, output
control, and other logic functions can be easily implemented.
2 FEATURES
Single power supply 2.4V 5.5V
13 seconds voice capacity are provided(@6KHZ sample rate)
Built in a 4-bit tiny controller
One 4-bit input port, two 4-bit output ports and three 4-bit I/O ports are provided
128*4 bits RAM are provided
40K*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
Two independent voice channels (Channel 1 + Channel 2
Buo1,Buo2)
Built in a PWM Direct Drive circuit and a fixed current D/A output
System clock : 2MHz
Low Power Reset
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
3 Block Diagram
IO1
IO2
IO3
IO4
IO5
Sampling Rate Counter
2
Timing
Generator
D/A
Timer
SRAM (128 nibbles)
ALU
Voice
Synthesizer
IO6
PWM
Address Pointers/ STACK
OSC
ROM
Program/Speech
40K
10 bits
4 PIN ASSIGNMENT
Symbol
I/O Function Description
P13 ~ P10
I
Bit3 ~ Bit0 of Input port 1
P23 ~ P20
I/O Bit3 ~ Bit0 of I/O port 2
P33 ~ P30
I/O Bit3 ~ Bit0 of I/O port 3
P43 ~ P40
O Bit3 ~ Bit0 of Output port 4
P53 ~ P50
O Bit3 ~ Bit0 of Output port 5
P63 ~ P60
I/O Bit3 ~ Bit0 of I/O port 6
VDD
P Positive power supply
GND
P Negative power supply
RST
I
Reset pin (active high)
OSC
O Oscillator / Crystal Out
BUO1/VO O
Positive
Output of PWM or DA output
BUO2
O Negative Output of PWM
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
5 FUNCTION DESCRIPTIONS
5.1. Oscillator
SNC538 accept RC type oscillator for system clock. The typical circuit diagram for
oscillator is listed as follow.
r
OSC
VCC
RC Oscillator
5.2. ROM
SNC538 contains substantial 40K words (10-bit) internal ROM. Program, voices and
other data are shared with this same 40K words ROM.
5.3. RAM
SNC538 contains 128 nibbles RAM. The 128 nibbles RAM are divided into eight
pages (page 0 to page 7, 16 nibble 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 SNC538 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 SNC538, any valid data transition (L H or H L)
occurring on any input port (P1) or IO ports (P2, P3 and P6) will lead SNC538 back to
normal operation mode.
5.5. Sampling Rate Counters
Ver: 1.2
November 26, 2002
3
2 independent sampling rate counters are dedicated to 2 individual voice channels 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.
SNC538
Two Channel Direct Drive Speech Controller
5.6. I/O Ports
P1 is a 4-bit input port, P2/P3/P6 are three 4-bit I/O ports and P4/P5 are two 4-bit
output 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
Read Control
PAD
Weak
Input Port Configuration (P10~P13)
Port Data
Port Status
To Internal Data Bus
Read Control
PAD
Weak
I/O Port Configuration (P20~P23, P30~P33, P60~P63)
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
PAD
weak
Port Data
Port Status
Output Port Configuration (P40~P43, P50~P53)
Note: All weak N-MOS's can serve as pull-low resistors.
5.7. 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.
Mode
38.5KHZ
P33
PAD
"1"
5.8. DAC & PWM
SNC538 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 SNC538. 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.
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
Input data
Typical value of output current (mA)
0 0
1 3/127
...
N n*(3/127)
...
127 3
VCC
BUO1/VO
1K
DAC output
PWM: A PWM (pulse width modulation) circuit is built-in SNC538. PWM can
convert input digital data into pulse trains with suitable different pulse width. The
maximum resolution of PWM is 7 bits. Two huge output stage circuits are
designed in SNC538. With this advanced circuit, the chip is capable of driving
speaker directly without external transistors. The recommended application
circuit is illustrated as follows.
BUO1/VO
BUO2
PWM Output
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
6 ABSOLUTE MAXIMUM RATING
Items
Symbol
Min
Max
Unit.
Supply Voltage
V
DD
-V -0.3 6.0
V
Input Voltage
V
IN
V
SS
-0.3 V
DD
+0.3 V
Operating Temperature
T
OP
0 55.0
o
C
Storage Temperature
T
STG
-55.0 125.0
o
C
7 ELECTRICAL CHARACTERISTICS
Item
Sym. Min. Typ. Max. Unit
Condition
Operating Voltage
V
DD
2.4 3.0 5.5 V
Standby current
I
SBY
- - 3.0 uA V
DD
=3V, no load
Operating Current
I
OPR
- - 350 uA V
DD
=3V, no load
Input current of
P1, P2, P3, P6
I
IH
- 3.0
10.0
uA V
DD
=3V,V
IN
=3V
Drive current of
P2, P3, P4, P5, P6
I
OD
- 4 - mA V
DD
=3V,V
O
=2.4V
Sink Current of
P2, P3, P4, P5, P6
I
OS
- 6 - mA V
DD
=3V,V
O
=0.4V
Drive current of
P2, P3, P4, P5, P6
I
OD
- 5 - mA V
DD
=4.5V,V
O
=3.9V
Sink Current of
P2, P3, P4, P5, P6
I
OS
- 9 - mA V
DD
=4.5V,V
O
=0.4V
Drive current of Buo1
I
OD
100 120 - mA VDD=3V,Buo1=1.5V
Sink Current of Buo1
I
OS
100 120 - mA VDD=3V,Buo1=1.5V
Drive Current of Buo2
I
OD
100 120 - mA VDD=3V,Buo2=1.5V
Sink Current of Buo2
I
OS
100 120 - mA VDD=3V,Buo2=1.5V
Oscillation Freq.
F
OSC
- 2.0 - MHz
V
DD
=3V
IR Carrier Frequency
Fir
-
38.5
-
KHz Fosc=2MHz
Ver: 1.2
November 26, 2002
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SNC538
Two Channel Direct Drive Speech Controller
8 APPLICATION CIRCUIT
G
N
D
TR1
TR2
TR3
TR4
TR5
TR6
P1
0
TR7
TR8
TR9
TR
10
TR
11
TR
12
TR1
3
TR1
4
TR1
5
TR1
6
TR1
7
TR1
8
TR1
9
TR2
0
TR2
1
TR2
2
TR2
3
TR2
4
TR2
5
TR2
6
TR2
7
TR2
8
TR2
9
TR3
0
TR3
1
TR3
2
P1
1
P1
2
P1
3
P2
0
P2
1
P2
2
P2
3
P4
0
P4
1
P4
2
P4
3
SNC538
P30
P31
P32
P33
OS
C
VO
1
V
D
D
1
K
8
0
5
0
R
VD
D
VD
D
RST
0.
1
u
F
D/A Speaker Output
32 Scan Keys
Ver: 1.2
November 26, 2002
8
SNC538
Two Channel Direct Drive Speech Controller
9 BONDING PAD
(0.00,0.00)
1
2
3
4
5
6
7
8
9
13
14
15
16
17
18
19
20
21
22
30 29 28 27
23
24
25
26
33 32 31
11
12
10
P10
P11
P12
O
S
C
G
N
D
BUO
1
V
D
D
BUO
2
GN
D
RST
P21
P22
P23
P30
P31
P32
P33
P40
P41
P60
P53
P52
P51
VDD
P42
P43
P50
P63
P62
P61
GND
P13
P20
Note: The substrate MUST be connected to Vss in PCB layout.
Ver: 1.2
November 26, 2002
9
SNC538
Two Channel Direct Drive Speech Controller
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Ver: 1.2
November 26, 2002
10
SNC538
Two Channel Direct Drive Speech Controller
Ver: 1.2
November 26, 2002
11
GREEN VOICE
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