The STC15 series is a family of 8051-core microcontrollers from STC Micro (宏晶科技) with significant upgrades over the original 8051 design:
Single-cycle core → 10x faster than classic 8051 🔥High-speed internal oscillator (up to 35MHz)On-chip EEPROM Multiple UARTs (up to 4!) Rich peripherals like ADC, PWM, timers, WDT, I2C, SPI
📦 Most Common STC15 Variants Compared
Feature / Model STC15F104W STC15F204EA STC15W408AS STC15F2K60S2 STC15L204EA Flash 1 KB 4 KB 8 KB 60 KB 4 KB RAM 256 B 512 B 512 B 1 KB 512 B EEPROM No 512 B 1 KB 1 KB 512 B GPIO Pins 6 18 26–35 35 18 ADC Channels (10-bit) None 8 8 8 8 PWM Channels None 4 6 6 4 UARTs 1 1 2 4 1 Timers 2 4 4 4 4 Speed (MHz) Up to 30 MHz Up to 35 MHz Up to 35 MHz Up to 35 MHz Up to 35 MHz Operating Voltage 3.3–5.5V 3.3–5.5V 3.3–5.5V 3.3–5.5V 1.8–5.5V ✅Package Types SOP8 SOP20/DIP20 SOP16/20/28 LQFP44/DIP40 SOP20
📌 Summary of Key Models
⚡ STC15F104W — Minimalist MCU
💡 Great for ultra-simple applications (e.g., blinkers, switch logic)
No ADC, no EEPROM
6 I/O pins max
🧩 STC15F204EA — Entry-level all-rounder
8 ADC channels
Basic PWM and 512B EEPROM
Compact and cost-effective
🚀 STC15W408AS — Mid-range beast
Fast, with 8KB Flash and dual UARTs
Great for serial communication, motor control, and analog sensors
Fully featured with PWM, ADC, EEPROM, etc.
🧠 STC15F2K60S2 — Powerhouse MCU
60 KB Flash and 4 UARTs 🤯
Excellent for communication-heavy or multitasking applications
Ideal for larger projects, modbus devices, or sensor hubs
🌱 STC15L204EA — Low-voltage version
Works down to 1.8V , perfect for battery-powered devices
Small size, low power
Still packs ADC, EEPROM, and PWM
🔌 Common Features Across STC15 Series
Feature Description Core Enhanced 8051 (single-cycle, 10x faster) ISP / IAP Yes (UART-based programming & EEPROM access) Timers Timer 0–3, 16-bit and 8-bit WDT Built-in Watchdog Timer Oscillator Internal high-speed up to 35MHz Clock Source Internal RC, external crystal or clock ADC Resolution 10-bit (on supported models) PWM Multiple channels (hardware-level) I²C / SPI Some models support I2C and SPI
💡 Which STC15 Should You Use?
Scenario Recommended Chip Simple blinker or LED controller STC15F104W (super cheap) Basic analog + digital combo STC15F204EA Dual UART sensor + motor system STC15W408AS Multiple serial devices (4 UART) STC15F2K60S2 Battery-powered low-voltage gadgets STC15L204EA
🧰 Development Tools
Flashing Tool : STC-ISP (connect via UART1)IDE : Keil uVision + STC header filesC Libraries : STC-CLib, or write pure C with register accessDebugging : No JTAG/SWD — use UART + printf() debugging
🛠 Sample Projects Ideas
💡 LED effects with PWM (STC15F204EA or W408AS)
🖲️ Analog joystick → UART stream (ADC + UART)
📡 UART-to-UART repeater (STC15F2K60S2 with 4 UARTs!)
🔋 Low-power sensor node with EEPROM (STC15L204EA)
Download STC15series MCU Data Sheet (English)
📡Broadcast the signal — amplify the connection.
