STM8S105K4U6A ST Mainstream Access Line 8-bit MCU 16KB Flash 16MHz CPU 10-bit ADC 1KB EEPROM UFQFPN-32

STM8S105K4U6A Product Overview

The STM8S105K4U6A is a mainstream access line 8-bit MCU from STMicroelectronics, classified as a medium-density device in the STM8S family reference manual (RM0016). Featuring a 16 MHz advanced STM8 core with Harvard architecture and 3-stage pipeline, it delivers up to 20 MIPS processing capability. It integrates 16 KB Flash, 2 KB RAM, and 1 KB true data EEPROM (endurance: 300k write/erase cycles — 3x the typical industry standard). On-chip peripherals include a 10-bit ADC (7 channels with scan mode and analog watchdog), 16-bit advanced control timer (4 CAPCOM channels, 3 complementary outputs with dead-time insertion), two 16-bit general-purpose timers (total 5 CAPCOM channels), 8-bit basic timer, auto wakeup timer, window and independent watchdog timers, and UART (with clock output for synchronous operation, SmartCard, IrDA, LIN master mode), SPI (up to 8 Mbit/s), and I2C (up to 400 Kbit/s) interfaces. Packaged in UFQFPN-32 (5×5×0.55 mm) with 25 I/Os and highly robust I/O design immune against current injection, it operates from 2.95 V to 5.5 V over -40 °C to 85 °C. Ideal for industrial control, sensor modules, consumer electronics, automotive applications, and cost-sensitive embedded solutions.

STM8S105K4U6A Core Features

Advanced Core: 16 MHz STM8 core, Harvard architecture, 3-stage pipeline, extended instruction set, up to 20 MIPS, up to 37 external interrupts, 32 nested interrupts Memory: 16 KB Flash (20-year data retention at 55 °C after 10k cycles), 2 KB RAM, 1 KB true data EEPROM (300k write/erase cycles) 10-bit ADC: 7 multiplexed channels, ±1 LSB accuracy, scan mode and analog watchdog Advanced Control Timer: 16-bit, 4 CAPCOM channels, 3 complementary outputs, dead-time insertion and flexible synchronization General-Purpose Timers: 2x 16-bit, total 5 CAPCOM channels (IC/OC/PWM); 8-bit basic timer with 8-bit prescaler Auto Wakeup Timer: Wakeup from Active-halt mode Dual Watchdogs: Window watchdog + Independent watchdog with separate clock source Communication Interfaces: UART with clock output for synchronous operation, SmartCard, IrDA, LIN master mode; SPI up to 8 Mbit/s; I2C up to 400 Kbit/s Clock System: 4 master clock sources (external clock, crystal oscillator, user-trimmable 16 MHz RC, low-power 128 kHz RC), clock security system with monitor Low-Power Modes: Wait, Active-halt, Halt; individually switchable peripheral clocks High Reliability: Low-consumption POR/PDR, highly robust I/O design immune against current injection, 96-bit unique ID per device UFQFPN-32 Package: 5×5×0.55 mm, 25 I/Os, suitable for space-constrained designs Wide Operating Range: 2.95 V to 5.5 V, -40 °C to 85 °C Development Support: Embedded SWIM single-wire interface for fast on-chip programming and non-intrusive debugging

STM8S105K4U6A Applications

Industrial Control: PLCs, sensor transmitters, RS-485 communication nodes, small actuator control; wide temperature reliability LED Lighting: Dimming control, RGB strips, switching power supplies; direct PWM drive Battery Management: Protection boards, fuel gauges, charge management; low-power modes reduce standby consumption Home Appliances: Induction/microwave oven panels, small appliance main controllers Sensor Modules: Temperature/humidity/gas sensing; 10-bit ADC + I2C/UART flexible networking Consumer Electronics: Remote controls, electric toothbrushes, electronic toys; high-value 32-pin solution Motor Control: Fans, pumps, small motors; advanced timer with complementary PWM and dead-time Automotive Electronics: Vehicle light control, window anti-pinch, automotive sensor nodes (non-safety-critical)

STM8S105K4U6A Key Advantages

300k High-Endurance EEPROM: 1 KB true data EEPROM with 300k write/erase cycles (3x standard endurance), reliably storing calibration parameters and operation logs without external memory ICs 20 MIPS High Performance: 16 MHz STM8 core with Harvard architecture and 3-stage pipeline, delivering up to 20 MIPS for complex control algorithms Ultra-Cost-Effective: 16 KB Flash + 2 KB RAM + 1 KB true EEPROM + 10-bit ADC (7 channels) + multiple timers + UART/SPI/I2C in UFQFPN-32 compact package, minimizing BOM cost Advanced Timer for Motor Control: 4 CAPCOM channels, 3 complementary outputs with dead-time insertion, driving half-bridge circuits and motor control Ultra-Compact Package: 5×5 mm UFQFPN-32 package, ideal for space-constrained portable devices and miniature sensor modules Robust & Reliable: 4 clock sources + clock security system, low-consumption POR/PDR, independent watchdog with separate clock source Mature Ecosystem: STM8 classic architecture, rich documentation, low-cost SWIM debug, shortening development cycles Stable Supply Chain: STMicroelectronics mainstream access line with massive global shipments, ensuring stable supply

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FAQ:

1. What is the STM8S105K4U6A and its key specifications?
   The STM8S105K4U6A is an 8‑bit microcontroller from STMicroelectronics based on the STM8 core at up to 16 MHz. It provides 16 KB of Flash program memory, 2 KB of SRAM, and 1 KB of true data EEPROM. Key peripherals include a 10‑bit ADC, an advanced control timer (TIM1) with 3 complementary PWM pairs, general‑purpose timers (TIM2, TIM4), and communication interfaces: UART, SPI, I2C. It is housed in an ultra‑compact UFQFPN32 package (5 mm × 5 mm) with 28 I/O pins and operates from ‑40 °C to +85 °C. It does not include a CAN controller, making it a space‑saving, cost‑effective solution for motor control and sensing applications without networking requirements.

2. How does the STM8S105K4U6A differ from the STM8S105K4T6C?
   Electrically and functionally they are identical — same 16 KB Flash, 2 KB SRAM, 1 KB EEPROM, identical peripherals (including TIM1 with three complementary PWM pairs), and same I/O count (28 pins). The only difference is the package: the K4U6A uses a UFQFPN32 (5×5 mm QFN), while the K4T6C uses an LQFP‑32. Choose the K4U6A when board space is extremely tight and reflow soldering is available; choose the K4T6C for easy hand‑soldering and prototyping.

3. What is the difference between STM8S105K4U6A and STM8S105K6T6C?
   Both are 32‑pin STM8S105 series MCUs. The K6T6C provides double the Flash — 32 KB vs 16 KB on the K4U6A — but both have identical 2 KB SRAM and 1 KB EEPROM. The K4U6A is available only in a UFQFPN32 (QFN) package, while the K6T6C typically uses an LQFP‑32. Both feature the same TIM1 motor‑control timer and lack CAN. Pick the K4U6A if 16 KB of Flash is sufficient and you need the smallest possible footprint; choose the K6T6C if you need extra code space or prefer an LQFP package.

4. Does the STM8S105K4U6A have a CAN bus interface?
   No. The STM8S105K4U6A does not include a CAN controller. It is designed for applications that require robust motor control and standard communication (UART, SPI, I2C) without automotive or industrial CAN networking. If CAN is required, consider the STM8S207 or STM8S208 series.

5. Can the STM8S105K4U6A drive a brushless DC motor directly?
   Yes. The advanced timer TIM1 provides 3 complementary PWM pairs with programmable dead‑time insertion and a break input. This allows the MCU to directly control a three‑phase inverter or a BLDC motor half‑bridge without external dead‑time logic. It is widely used in compact motor drives for fans, pumps, and power tools.

6. What are the ADC specifications of the STM8S105K4U6A? How many analog channels are available?
   It features a 10‑bit successive‑approximation ADC. Internally, the ADC supports up to 16 multiplexed analog input channels. In the 32‑pin UFQFPN package, depending on digital pin configuration, typically 7 to 10 external analog channels are accessible. The ADC can also measure an internal voltage reference and can be triggered by TIM1 for synchronized motor‑current sensing.

7. How much memory does the STM8S105K4U6A have?
   It provides 16 KB of Flash program memory, 2 KB of SRAM, and 1 KB of true data EEPROM. This memory configuration is well‑suited for compact motor‑control algorithms, simple communication stacks, and sensor acquisition tasks.

8. What package does the STM8S105K4U6A use and how many I/O pins are there?
   It comes in a UFQFPN32 package — a 32‑pin QFN measuring just 5 mm × 5 mm with a 0.5 mm pitch. It provides 28 general‑purpose I/O pins. This ultra‑compact, low‑profile package is ideal for space‑constrained designs such as small motor controllers, portable sensors, and compact actuators.

9. Can the STM8S105K4U6A be powered directly from 5 V?
   Yes, it is a true 5 V‑capable microcontroller. The operating voltage range is 2.95 V to 5.5 V, so it can be powered directly from a standard 5 V rail, USB, or a loosely regulated supply. All I/Os are 5 V tolerant, simplifying interface to legacy TTL and CMOS logic.

10. How to program and debug the STM8S105K4U6A? What are its typical applications?
    Programming and debugging use the single‑wire SWIM interface. A low‑cost ST‑LINK/V2 is the standard tool. Firmware can be developed with STVD + Cosmic C or the open‑source SDCC compiler, and ST provides standard peripheral libraries. Typical applications include compact motor drives (small fans, pumps, power tools), home appliances, industrial sensors, and battery‑powered actuators. Its tiny QFN footprint, three‑phase motor timer, and 5 V operation make it a very popular choice for cost‑sensitive, space‑limited embedded designs.