SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

1 INTRODUCTION

SNC521 is a one-channel voice synthesizer IC with PWM direct drive circuit. It

built-in a 4-bit tiny controller with two 4-bit I/O ports. By programming through the tiny
controller in SNC521, 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

10 seconds voice capacity are provided(@6KHZ sample rate)

Built in a 4-bit tiny controller

Two 4-bit I/O ports are provided

64*4 bits RAM are provided

32K*10 ROM size are provided for voice data and program

Maximum 16k program ROM is provided

IR carrier signal is provided

Built in a high quality speech synthesizer

Adaptive playing speed from 2.5k-20kHz is provided

One voice channel

Built in a PWM Direct Drive circuit and a fixed current D/A output

System clock : 2MHz

Low Power Reset

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

3 Block Diagram

4 PIN ASSIGNMENT

Symbol

I/O Function Description

P23 ~ P20

I/O Bit3 ~ Bit0 of I/O port 2

P33 ~ P30

I/O Bit3 ~ Bit0 of I/O port 3

VDD

P Positive power supply

GND

P Negative power supply

RST

Reset pin (active high)

OSC I

Oscillator

Input

BUO1/VO O

Positive

Output of PWM or DA output

BUO2

O Negative Output of PWM

ROM

Program/Speech

32K

�10 bits

OSC

Address Pointers/ STACK

PWM

Voice

Synthesizer

ALU

SRAM (64 nibbles)

Timer

D/A

Timing

Generator

Sampling Rate Counter

IO port 3

IO port 2

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

5 FUNCTION DESCRIPTIONS

5.1. Oscillator

SNC521 accept RC type oscillator for system clock. The typical circuit diagram for
oscillator is listed as follow.

5.2. ROM

SNC521 contains substantial 32K word (10-bit) internal ROM. Program and voices
are shared with this same 32K word ROM.

5.3. RAM

SNC521 contains 64 nibbles RAM. The 64 nibbles RAM are divided into four pages
(page 0 to page 3, 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 3) 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 SNC521 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 SNC521, any valid data transition (L H or H L)
occurring on any IO ports (P2 and P3) will lead SNC521 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.

OSC

VCC

RC Oscillator

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

5.6. I/O Ports

P2 and 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
P2 and P3 can reactivate the chip when the chip is in power-down stage.

I/O Port Configuration (P20~P23, P30~P33)

Note: Weak N-MOS can serve as pull-low resistor.

5.7. DAC & PWM

SNC521 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 SNC521. 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.

Port Data

Port Status

To Internal Data Bus

Read Control

PAD

Weak

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

Input data

Typical value of output current (mA)

0 0
1 3/127
...
N n*(3/127)
...
127 3

DAC output

PWM: A PWM (pulse width modulation) circuit is built-in SNC521. 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 SNC521. With this advanced circuit, the chip is capable of driving
speaker directly without external transistors. The recommended application
circuit is illustrated as follows.

PWM Output

VCC

BUO1/VO

BUO2

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

6 ABSOLUTE MAXIMUM RATING

Items

Symbol

Min

Max

Unit.

Supply Voltage

-V -0.3 6.0

Input Voltage

-0.3 V

+0.3 V

Operating Temperature

0 55.0

Storage Temperature

STG

-55.0 125.0

7 ELECTRICAL CHARACTERISTICS

Item

Sym. Min. Typ. Max. Unit

Condition

Operating Voltage

2.4 3.0 5.5 V

Standby current

SBY

- 2.0

5.0

=3V , no load

=4.5V, no load

Operating Current

OPR

- 300

700

uA V

=3V , no load

=4.5V, no load

Input current of
P2, P3

- 3.0

10.0

uA V

=3V,V

=3V

Drive current of
P2, P3

- 4 - mA V

=3V,V

=2.4V

Sink Current of
P2, P3

- 6 - mA V

=3V,V

=0.4V

Drive current of Buo1

100 120 - mA VDD=3V,Buo1=1.5V

Sink Current of Buo1

100 120 - mA VDD=3V,Buo1=1.5V

Drive Current of Buo2

100 120 - mA VDD=3V,Buo2=1.5V

Sink Current of Buo2

100 120 - mA VDD=3V,Buo2=1.5V

Oscillation Freq.

OSC

- 2.0 - MHz

=3V

SNC521

One Channel Direct Drive Speech Controller

Ver: 1.3

August 26, 2003

11 DISCLAIMER

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The application circuits illustrated in this document are for reference purposes only.
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Applications involving unusual environmental or reliability requirements, e.g. military
equipment or medical life support equipment, are specifically not recommended
without additional processing by SONIX for such application.

Электронный компонент: SNC521