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Epson Shipping Samples of a 32-Bit Microcontroller with Dedicated Sound Hardware

S1C31D50 MCU with ARM® Cortex®-M0+ processor* the ideal sound solution for home appliances and electronics

Seiko Epson Corporation (TSE: 6724, “Epson”) has begun shipping samples of the S1C31D50, a 32-bit microcontroller with dedicated sound hardware for 2-channel sound. Epson plans to produce 200,000 units per month of each model.


Sound is becoming an increasingly popular feature in home electronics, remote controllers for home appliances, industrial devices, health and fitness equipment with guidance systems, and alarms in office buildings, shopping complexes, and factories. This MCU is ideal for all these applications. An ARM® Cortex®-M0+ processor integrated with a dedicated HW Processor provides 2-channel sound on a single MCU chip. The use of two channels enables music and voice to be played simultaneously, lending audio guidance greater elegance and warmth. Voice speed can also be flexibly adjusted.

The MCU’s dedicated HW Processor sound hardware boasts a pair of special features. First, the HW Processor plays sound without requiring CPU resources, so CPU resources can be allocated to other processes even during sound playback. The use of a high-compression algorithm (16 kbps @ 16 kHz) shrinks the size of sound data memory, making it possible to provide a large amount of sound data and sound data in multiple languages. Epson also offers a PC tool that provides a development environment for easily creating sound data in Japanese, English, Chinese, and Korean without studio recording. 
Second, the MPU also has a self-memory check function that can detect failures in built-in RAM, built-in Flash, and external SPI-Flash memories without using CPU resources.

Epson is committed to helping its customers improve the performance of their products with solutions that leverage Epson’s efficient, compact, and precision technologies.

* A processor designed by U.K-based ARM Limited, the ARM® Cortex®-M0+ is ARM’s most energy-efficient processor and by far the most widely used processor in the market.
ARM and Cortex are registered trademarks of ARM Limited (or its subsidiaries) in the EU and other countries. All rights reserved.

Key Product Features

  • Dedicated hardware block for independently executing functions. The HW Processor executes the following functions without using CPU resources:
    • Sound play processing
      • 2-channel mixing sound (for playing background music + voice)
      • Voice speed conversion (playback speed adjustable in 5% increments between 75% and 125%)
      • The sampling rate of 15.625 kHz is high enough for background music as well as voice.
      • High-compression voice decoding algorithm with high sound quality (16/24/32/40 kbps)
    • Self-memory check function
      • Built-in RAM (R/W check, MARCH-C START)
      • Built-in Flash checksum, CRC
      • External QSPI-Flash checksum, CRC
    • Simple HW Processor interface
      • Just set functions and commands in the special register and then start
  • Easily add voice later
    • Sound data is easily added simply by writing the sound data and sentence information (sound data number and joining information
  • Development environment
    Epson sound creation PC tool
    • Studio recording is not needed. Simply use the PC tool to create all the sound data you need (languages supported: Japanese, English, Mandarin Chinese, Korean)
    • Sound data, which is assigned a number in the PC tool, can be played back by specifying the assigned number in the HW processor register, so there is no need to create and evaluate codes for linking sound data, etc.
    • Your WAV format sound data is easily imported into the PC tool

Product Specifications

Product number S1C31D50
CPU core ARM® Cortex®-M0+ 32-bit RISC processor
Flash memory 192 kB (for both program and sound data)
RAM 8 kB (22 kB when not playing audio)
HW Processor Sound decoding (original Epson format, 15.625 kHz sampling rate, 2-channel mixing, voice speed conversion
Self-memory check function (built-in Flash & RAM, external QSPI-Flash)
Sound DAC Sampling rate: 15.625 kHz, mono
Serial interfaces UART, SPI, and I2C: 3 channels each. QSPI: 1 channel
Analog-digital converter 8 inputs, max. (12-bit successive-approximation ADC)
Supply voltage detector 32 level (1.7 V – 4.3 V)
DMA 4 channels (memory ⇔ memory, memory ⇔ peripheral)
Radio-frequency converter (RFC) 1-channel, low-resistance sensor A-D conversion, CR oscillation with 24-bit counters
Infrared remote controller 1 channel (can be used to generate EL lamp driving waveforms)
Timers 16-bit timer (8 channels), 16-bit PWM (2 channels), watchdog timer (WDT), real-time clock (RTC)
Power supply voltage 1.8 V – 5.5 V
SPI-Flash interface voltage 3.3 V (3.0 V – 3.6 V)
Operating frequency 16 MHz (VD1 voltage mode: mode 0)
2 MHz (VD1 voltage mode: mode 1)
Power consumption* RUN: 250 uA/MHz (VD1 voltage mode: mode 0) 
RUN: 155 uA @ 1 MHz (VD1 voltage mode: mode 1) 
SLEEP: 0.43 uA, RTC mode: 0.9 uA
I/O ports Max. 91 
Of which up to 32 may be Universal Port Multiplexers (UPMUX)
Packages TQFP12-48 (size: 7 mm x 7 mm. Pin pitch: 0.5 mm)
TQFP13-64 (size: 10 mm x 10 mm. Pin pitch: 0.5 mm)
TQFP14-80 (size: 12 mm x 12 mm. Pin pitch: 0.5 mm)
QFP15-100 (size: 14 mm x 14 mm. Pin pitch: 0.5 mm)

*At typical environmental values, SLEEP mode, RTCA = On, 25 degrees Celsius


  1. Please see the website below for further details about the S1C31D50 and the rest of the products in the S1C31 series (the S1C31D50, S1C31D01, and S1C31W74).
  2. Further details about the 16-bit S1C17 series are available on the following website:

To receive even more information like technical data sheets, samples, EVBs or price information please contact an Ineltek office within your area or contact us at