Adafruit CH552 QT Py – A 8051 Powered Dev Board with RGB LED and STEMMA QT

Adafruit CH552 QT Py – A 8051 Powered Dev Board with RGB LED and STEMMA QT


Adafruit just announced Adafruit CH552 QT Py and this board ranks in the top part of my weird tech list. The MCU used in this is a WinChipHead (WCH) CH552 has an E8051 Core. with 16 kilobytes of flash memory but only about 1.25 kilobytes of RAM, and the most weird thing about this it has a built-in USB physical interface (PHY).

An 8051 with USB! surprising but true. The QT Py follows the tiny Seeed Studio Xiao form factor, measuring just 20 by 17.5 millimeters. It features a microcontroller with a USB-C interface for programming and an RGB NeoPixel LED for visual feedback. With 10 GPIO pins and castellated edges, it offers flexibility for soldering header pins or direct attachment to a circuit board.

The CH552 has specific programming requirements and doesn’t support MicroPython or CircuitPython. If using the Arduino IDE, you’ll need the ch55xduino board support package, which has a limited-feature compiler. Not all Arduino libraries are compatible, so testing example code is advisable. Check out Toby Chui’s project for an example using the CH552: a hotplate controlled by the CH552 to regulate the heating profile.

Adafruit CH552 Specifications:

  • Compact, Seeed Xiao-compatible design
  • USB Type-C connector with Micro B adapter compatibility
  • CH552 8-bit 8051 microcontroller core, 3.3V logic, and 16 MHz internal oscillator
  • Native USB support
  • Integrated RGB NeoPixel LED
  • Versatile GPIO layout:
    • A2 pin serves as MOSI for hardware SPI and one of only 4 ADC pins
    • 4 x 8-bit analog inputs (A0-A3)
    • 3 x PWM outputs
    • I2C port with STEMMA QT plug-n-play connector
    • Hardware UART and SPI
    • 4 x Capacitive Touch inputs on A0-A3 pins, no extra components needed
  • 3.3V regulator with 600mA peak output
  • Reset switch and bootloader for easy code restart or USB ROM bootloader mode entry

Adafruit is now offering the CH552 8051 QT Py at an enticing price of $4.95. This adorable board is readily available, inviting you to delve into its distinctive features and capabilities.

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About Debashis Das

Tech Content Creator | Hardware Design Engineer | IoT Enthusiast | Digital Storyteller | Video Creator | From crafting digital dialogues at Semicon Media to orchestrating online engagement at, my journey is about making tech talk interesting and accessible. In the quiet corners of the day, I advocate for easier tech education, one tutorial at a time. Let's connect and keep the digital dialogue going!

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