Selecting a microcontroller (MCU) involves more than simply comparing performance and price. Requirements vary significantly from product to product. Focusing on the wrong priorities can increase development effort and costs, and even weaken market competitiveness. For example, low power consumption is important for remote controls and activity trackers, while measurement accuracy and reliability are key considerations for temperature controllers and multimeters. Long-term availability and noise immunity are also important selection criteria for major home appliances and home equipment. This article organizes the points to check when selecting an MCU, and explains why they matter, across three categories: consumer products, industrial and home equipment, and healthcare devices. Use it as a reference when choosing the best MCU for your products.
Key MCU Selection Criteria - Consumer Products
| Selection criterion | What to check | Why it matters | Product examples where especially important |
|---|---|---|---|
| Power consumption | Operating current, sleep current, wake-up time | Directly affects battery life and energy efficiency |
Watches, remote controls, electronic dictionaries |
| MCU unit price | Purchase price for volume production | Directly affects product profit margins and selling prices | All products |
| Memory capacity | Flash and RAM capacity | Affects firmware implementation and future feature additions | Label printers, home appliances, electronic toys |
| CPU performance | Clock frequency, processing capability | Determines UI responsiveness and control performance | Label printers, robot vacuum cleaners, air purifiers |
| Startup speed | Startup time after reset | Affects perceived quality when users operate the product | Remote controls, electronic locks |
| Package size | Mounting area, pin count | Enables smaller products and lower PCB costs | Watches, smart tags, remote controls |
| GPIO count | Number of input/output pins | Provides flexibility for connecting keys, displays, and sensors | Label printers, electronic toys, cooking appliances |
| Timer functions | Number of timers, PWM channels | Used for motor control and display control | Electric fans, electric toothbrushes, humidifiers |
| ADC performance | Resolution, conversion speed, accuracy | Enables accurate acquisition of sensor data | Thermo-hygrometers, temperature-control devices |
| Communication interfaces | UART, I²C, SPI, etc. | Facilitate connections to peripheral ICs | Major home appliances, label printers |
| LCD control functions | Availability of an integrated LCD driver | Reduce external components and power consumption | Watches, timers, electronic meters |
| Motor control functions | PWM, comparators, control functions | Help reduce motor noise and improve efficiency | Electric fans, vacuum cleaners, power tools |
| Integrated EEPROM / data retention | Storage capacity, write endurance | Retain settings and historical data | Label printers, air conditioners, rice cookers |
| Watchdog timer (WDT) | WDT types, operating conditions | Required for automatic recovery from software faults | Major home appliances, electronic locks |
| Noise immunity | ESD and EMC performance | Prevents malfunctions and resets | Microwave ovens, induction cooktops, washing machines |
| Operating temperature range | Guaranteed temperature range | Ensures reliability in the intended installation environment | Refrigerators, water-heater remote controls, outdoor sensors |
| Development environment | IDE, compiler, debugging tools | Reduces development effort and improves quality | All products |
| Software resources | Sample code, libraries | Shorten development time and reduce bugs | IoT home appliances, smart devices |
| Long-term availability | Years of continued production, roadmap | Required for continued product sales and maintenance support | Major home appliances, home-equipment remote controls |
| Manufacturer support | Technical support framework | Enables faster resolution of issues during development and after mass production | All products |
Overview and Features of Epson MCUs for Consumer Products
Kitchen appliances such as microwave ovens and rice cookers, as well as wall-mounted remote controls for water heating and ventilation, need to combine easy-to-read displays, clear audible feedback, and reliable temperature control in a single operating panel within a 5 V circuit system. The S1C17M series comprises standard MCUs with Epson's proprietary 16-bit CPU, supporting an operating voltage range of 1.8-5.5 V. These MCUs can integrate the operating-panel functions into a single chip. Models with a built-in LED controller can drive LED displays directly without an external driver and support brightness adjustment, such as dimming at night. In addition to a sound generator for producing operation sounds and completion melodies, the series includes a 12-bit ADC and a 24-bit R/F converter, allowing thermistor-based temperature sensing to be handled on the same chip. Models with a built-in LCD driver or EEPROM also support timer displays and retention of user settings. An internal oscillator with ±1% accuracy can eliminate the need for an external resonator. UPMUX, which allows pin assignments to be changed, together with low-pin-count packages, helps reduce panel PCB size and provides greater design flexibility.
Representative product page:
https://global.epson.com/products_and_drivers/semicon/products/micro_controller/16bit/#ac06
Key MCU Selection Criteria - Industrial and Home Equipment
| Selection criterion | What to check | Why it matters | Product examples where especially important |
|---|---|---|---|
| Long-term availability | Years of continued production, manufacturer's roadmap | Home equipment and industrial equipment are often sold for more than 10 years |
Time switches, temperature controllers, thermostats |
| Reliability | FIT rate, quality certifications, defect rate | Reduces maintenance costs resulting from field failures | Temperature controllers, PLC-related equipment, electricity meters |
| Operating temperature range | Guaranteed temperature range | Equipment is used in hot or cold environments, such as control panels and outdoor locations | Thermostats, outdoor measuring instruments, temperature controllers |
| Noise immunity | EMC, ESD, and EFT immunity | Stable operation is required even in environments with noise from inverters and relays | Time switches, temperature controllers, power monitoring equipment |
| MCU unit price | Purchase price | Affects cost competitiveness in mass-produced equipment | All products |
| Memory capacity | Flash and RAM capacity | Affects implementation of control logic and communication functions | Temperature controllers, electricity meters, multifunction timers |
| CPU performance | Clock frequency, processing capability | Directly affects PID control and computational performance | Temperature controllers, multimeters |
| ADC performance | Resolution, accuracy, conversion speed | Determines measurement accuracy and control quality | Multimeters, temperature controllers |
| Timer functions | PWM, capture, compare timers | Required for timing control and precise control processing | Time switches, control relays |
| RTC (real-time clock) | Availability of an integrated RTC, accuracy | Required for accurate timekeeping | Time switches, electricity meters |
| Communication interfaces | UART, SPI, I²C, CAN, RS-485 | Required for connections to host systems and networking | Temperature controllers, building equipment |
| GPIO count | Number of input/output pins | Provides sufficient connections for switches, relays, and displays | Time switches, temperature controllers |
| EEPROM / data retention functions | Storage capacity, write endurance | Retain settings and calibration data | Thermostats, multimeters |
| Watchdog timer (WDT) | WDT functions | Enable automatic recovery when a fault occurs | All products |
| Safety functions | Clock monitoring, voltage monitoring, CRC functions | Prevent equipment shutdowns and accidents caused by malfunctions | Temperature controllers, safety monitoring equipment |
| Security functions | Unauthorized-access prevention, code protection | Security measures are necessary as products become IoT-enabled | Smart thermostats, remote monitoring devices |
| Development environment | IDE, debugging functions | Improves quality and reduces development effort | All products |
| Software resources | Control libraries, communication stacks | Shorten development time | Temperature controllers, IoT home equipment |
| Manufacturer support | Technical support framework | Facilitates problem resolution during long-term operation | All products |
Overview and Features of Epson MCUs for Industrial and Home Equipment
Water and gas meters, temperature and humidity sensor nodes, and home-equipment controllers for underfloor heating and ventilation must provide both long-term operation without battery replacement and measurement accuracy that remains stable in field environments. The S1C31W series comprises low-power MCUs based on the Arm® Cortex®-M0+ core and supports an operating voltage range of 1.8-5.5 V. It brings long-term operation, high-accuracy measurement, and display functions together on a single chip. The 24-bit R/F converter converts changes in an external resistance into frequency. Relative measurement against a reference resistor enables temperature and humidity measurements that are resistant to environmental variations. A 12-bit ADC, an internal temperature sensor, and a reference-voltage generation circuit also help reduce external analog components. The integrated LCD driver supports options ranging from numerical displays read on-site to high-resolution dot-matrix displays, depending on the model. Low current consumption-approximately 0.3 µA in sleep mode and 0.7 µA with the RTC operating-combined with individually selectable peripheral clocks enables fine-grained power-saving designs. Models supporting operating temperatures up to +105 ℃ are also available, allowing installation in hot environments such as outdoor meter boxes, heat-trapping locations inside equipment, and pipe shafts. The supply-voltage detection circuit and watchdog timer support self-diagnostics in equipment installed for long periods. Processing speeds of up to 32 MHz and large-capacity Flash memory also support systems that handle communications and accumulate data.
Representative product page:
https://global.epson.com/products_and_drivers/semicon/products/micro_controller/armcore/index.html#ac02
Key MCU Selection Criteria - Healthcare Devices
| Selection criterion | What to check | Why it matters | Product examples where especially important |
|---|---|---|---|
| Power consumption | Operating current, sleep current, wake-up time | Directly affects battery life and continuous operating time | Activity trackers, blood glucose meters, pulse oximeters |
| ADC performance | Resolution, accuracy, noise performance | Enables accurate measurement of sensor signals | Blood pressure monitors, blood glucose meters, weighing scales |
| CPU performance | Processing capability, clock frequency | Required for sensor data processing and signal analysis | Activity trackers, electrocardiographs, blood pressure monitors |
| Memory capacity | Flash and RAM capacity | Required for data storage and implementation of analysis algorithms | Activity trackers, thermometers |
| MCU unit price | Purchase price | Affects product cost and profit margins | Digital clinical thermometers, blood pressure monitors |
| RTC (real-time clock) | Timekeeping accuracy | Required for recording measurement history and managing data | Activity trackers, blood pressure monitors |
| Communication interfaces | Bluetooth Low Energy (BLE), UART, SPI, I²C | Enable connectivity with smartphones and cloud services | Activity trackers, smart blood pressure monitors |
| Security functions | Encryption, secure boot, authentication functions | Protect personal health data | Activity trackers, insulin pens |
| GPIO count | Number of input/output pins | Used to connect sensors and displays | Blood pressure monitors, activity trackers |
| LCD/Display control functions | Availability of an integrated LCD driver | Reduce external components and power consumption | Thermometers, blood pressure monitors |
| EEPROM/data retention functions | Storage capacity, write endurance | Retain measurement history and settings | Blood pressure monitors, thermometers |
| Watchdog timer (WDT) | Fault detection functions | Required for automatic recovery from software faults | All products |
| Operating temperature range | Operating and storage temperature ranges | Maintain measurement accuracy and reliability | Thermometers, portable medical devices |
| Noise immunity | EMC and ESD immunity | Prevent false detection of weak biological signals | Blood pressure monitors, heart rate monitors |
| Timer functions | PWM, capture functions | Used for sensor driving and control | Insulin pens, blood pressure monitors |
| Safety functions | Voltage monitoring, CRC, clock monitoring | Prevent measurement errors caused by malfunctions | Insulin pens, blood pressure monitors |
| Development environment | IDE, debugging tools | Improves quality and shortens development time | All products |
| Software resources | BLE stacks, sensor libraries | Reduce development effort | Activity trackers, smart medical devices |
| Long-term availability | Years of continued production | Required for long-term sales of medical and healthcare devices | Blood pressure monitors, insulin pens |
| Manufacturer support | Technical support framework | Facilitates certification processes and resolution of defects | All products |
Overview and Features of Epson MCUs for Healthcare Devices
Home healthcare devices such as digital clinical thermometers and body composition monitors must combine long battery life, accurate measurement of very small signals, and displays that are easy for anyone to read. The S1C17W series comprises low-voltage, low-power microcontrollers with Epson's proprietary 16-bit CPU and an operating voltage range of 1.2-3.6 V. It meets all three requirements on a single chip. The 24-bit R/F converter converts resistance changes, such as those of a thermistor, into frequency for high-resolution measurement. Its relative-measurement method, using a reference resistor, is less susceptible to temperature drift and enables stable measurement without an external high-precision A/D converter or reference-voltage IC. A 12-bit ADC, an internal temperature sensor, and a reference-voltage generation circuit are also integrated, helping reduce analog components and calibration effort. The integrated LCD driver includes an LCD boost power supply and supports displays ranging from segments with large, easy-to-read numerals to dot-matrix displays showing measurement histories and graphs. Low current consumption-approximately 0.15 µA in sleep mode and 0.3 µA in HALT mode-enables long operation from a coin cell, even in devices that spend extended periods on standby. Models with a boost circuit for driving a buzzer or LED can also provide measurement-completion sounds and indicator lights without external components.
Representative product page:
https://global.epson.com/products_and_drivers/semicon/products/micro_controller/16bit/#ac08
The priorities for selecting a microcontroller vary greatly by product. Some products prioritize low power consumption, while others should emphasize measurement accuracy, reliability, or long-term availability. It is therefore important to evaluate MCUs against the applications and required specifications of your own products, rather than relying solely on examples from other companies or general principles. Use the points introduced here to organize your product requirements and help select the most suitable MCU.
