Voice MCU

Epson offers simplest speech IC without traditional studio recording by a person. Our sophisticated codec engine eliminates such studio recording and generates neutral human sound quality as well as high compression rate. The Epson Voice/Audio IC enables a seamless IC platform to transform almost any applications into user-friendly voice prompted devices.


Feature1. Sound Processing without CPU resource

Sound Processing without CPU resource

Dedicated HW processor achieves all sound processing

Like Software Sound operation.

  • No Stop by a lack of software resource
  • No limitation for other operation
  • No need to evaluate many condition for Sound play
    (e.g. Sound Play x software condition)

Feature2. Providing ease of listening to individual end users

  • Realtime Voice Speed/Pitch Conversion
    Providing ease of listening to individual end users
    Voice play with background music.
Providing ease of listening to individual end users

Feature3. Easy to prepare Voice Data

  • Epson Voice Data Creation PC Tool
    Easy to change/add (Suitable for Frequently/Emergency)
    No cost to create Voice data(No need studio, narrator fee)
    Existing wav files can be imported to the tool easily
Easy to prepare Voice Data

Feature4. Easy to implement Sound Play

  • Just set "Sentence Number" on Epson Voice Creation PC Tool to the specific register by Cortex
    Sentence Information(phrase structure, connection, delay etc) is including in Sound ROM
    Even if there is a change in the content of the voice data, if there is no change in the number, there is no need to change the SW

Feature4. Easy to implement Sound Play

Feature 5. Easy to expand Language support

  • Voice Data Creation PC Tool supports 12 language
  • Multi-SoundROM
Easy to expand Language support

Easy to expand Language support

Feature 6. Achieve small memory size

  • High Quality & High Compression Sound Algorithm
    1/4 size comparison with same sampling frequency(16kHz)
    Small size(2/3) comparison with even low sampling frequency(8kHz)
    Many sound data, long music can be stored.
    Multiple language can be integrated.
Achieve small memory size

Feature 7. Play melody/voice on Buzzer

  • Select Sound Output mode by a product requirement
    Buzzer(Electromagnetic Buzzer, Piezoelectric Buzzer)
Play melody/voice on Buzzer

Feature 8. Achieve Long Battery Life

  • Low Sleep current
  • Low Standby current
  • Quick clock wake-up
  • Low RUN current
Achieve Long Battery Life

Achieve Long Battery Life


Products lineup






192 KB (both program and voice)

96KB(both program and voice)


8KB(HW Processor is not active:+14KB)

10KB(HW Processor is not active:+12KB)

8KB(HW Processor is not active:+18KB)

Internal Oscillator 16/8/4MHz 1% with 32kHz external-OSC 16/8/4MHz ±1%@Ta=0~85℃
HW Processor ver1.00 ver2.00 ver3.00
Sound Play Algorithm EOV(EPSON Original High Compress & High Quality Format) / 16bit PCM
Sound Play channels 2ch Mixing Play(e.g. Ch.0:Voice, Ch.1:BGM)
Sampling Frequency 15.625kHz, (Suitable for Back Ground Music)
Bitrate EOV:16/24/32/40 kbps EOV:16/24 kbps
Multi-SoundROM Multiple independent Sound ROM data can be stored for multilingual support, etc.
Gapless Sound Play - supported -
Volume Setting supported(0db to -63.0db:0.5db step, silence)
Repeat Setting supported(1 to 254times, repeat until stop command)
Voice Speed Conversion 75% - 125% (5% step) Ver1.00 75% - 125% (5% step) Ver2.00
Voice Pitch Conversion - 75% - 125% (5% step)
Tone Generation - supported
Buzzer Voice/Melody - supported -
Serial Interface SPI(3ch), UART(3ch), I2C(3ch), QSPI(1ch)
ADC 12bit(max 8 port) 12bit(max 8port,1port for temperature sensor)
SVD VDD: 28 levels(1.8 to 5.0 V) / external voltage: 32 levels(1.2 to 5.0 V)
DMA 4ch (Memory ⇔ Memory, Memory ⇔ Peripheral)
RFC CR oscillation type 24-bit counters
Timers 16bit Timer(8ch), 16bit PWM(2ch), WDT, RTC
Power Supply 1.8V~5.5V VDD / 3.3v SPI-Flash interface power supply
Flash Programming 2.4 ~ 5.5 V 2.2 ~ 5.5 V
Power Consumption
- Standard Mode
- Low Power Mode
RUN:250uA/MHz (internal:1.8v) max 16MHz
RUN:150uA/MHz (internal:1.2v) max 1.8MHz SLEEP:0.46uA, RTC mode:0.95uA
RUN:215uA/MHz(internal:1.8v) max 16MHz
RUN:130uA/MHz(internal:1.2v) max 1.8MHz
SLEEP:0.34uA, RTC mode:0.90uA


P-TQFP048-0707-0.50(0.5mm pitch)
P-LQFP064-1010-0.50(0.5mm pitch)
P-TQFP080-1212-0.50(0.5mm pitch)
P-LQFP100-1414-0.50(0.5mm pitch)

P-TQFP032-0707-0.80(0.8mm pitch)
P-TQFP048-0707-0.50(0.5mm pitch)
P-LQFP064-1010-0.50(0.5mm pitch)
IEC-60730 Supported by Sample SW

Customer comments

Customer comments

Information downloads

S1C31D50 /D51Data Sheet PDF (1,232KB)

S1C31D50 /D51Technical Manual PDF (11,439KB)

Related information

*Please request after purchasing Epson evaluation board