Adafruit
Adafruit CH552 QT Py - 8051 Dev Board with STEMMA QT
· MPN: ADA5960
The Adafruit CH552 QT Py is a compact development board built around the WCH CH552, an enhanced 8-bit 8051 microcontroller. Running at 16 MHz with native USB...
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The Adafruit CH552 QT Py is a compact development board built around the WCH CH552, an enhanced 8-bit 8051 microcontroller. Running at 16 MHz with native USB device support, it packs a surprising amount of functionality into the tiny QT Py form factor with STEMMA QT / Qwiic I2C connectivity.
The CH552 features 16 KB program flash, 256 bytes of internal RAM, and 1 KB of xRAM with DMA support. Its native USB controller enables it to act as a CDC serial device or HID keyboard/mouse without additional hardware. The board is Seeed Xiao compatible in size and pinout, with castellated pads for surface-mount soldering.
Key Features
- CH552 8051 Core – Enhanced 8-bit microcontroller at 16 MHz, 3.3V logic
- 16 KB Flash / 256 B RAM / 1 KB xRAM – xRAM supports DMA
- Native USB Device – Full-speed USB for CDC serial, HID keyboard/mouse
- 10 GPIO Pins – Including 4× 8-bit ADC, 3× PWM, hardware UART, hardware SPI, I2C
- 4× Capacitive Touch – On A0–A3 pins, no additional components needed
- RGB NeoPixel LED – Built-in programmable LED
- STEMMA QT / Qwiic – Plug-and-play I2C connector for sensors and accessories
- USB-C Connector – For programming and power
- Reset + Bootloader Buttons – Easy access to USB ROM bootloader mode
- 3.3V Regulator – 600 mA peak output
- Castellated Pads – Seeed Xiao compatible for surface-mount soldering
Ideal For
- Learning and experimenting with 8051 architecture
- Custom USB device projects (HID, CDC serial)
- Ultra-low-cost embedded USB applications
- Compact projects requiring a minimal microcontroller
Package Contents
- 1× Adafruit CH552 QT Py development board
Jargon buster
Plain-language definitions for the technical terms used above.
- 3.3V regulator
- A 3.3V regulator is a power circuit that provides a steady 3.3 volts for parts that need that supply voltage. On a breakout board, it can let the sensor run safely even when the connected microcontroller or power source uses a higher voltage.
- ADC
- An analogue-to-digital converter reads a changing voltage and turns it into a number the microcontroller can use. It matters when connecting analogue sensors such as light, sound, or variable-resistor sensors.
- Bootloader
- Small starter software on a microcontroller that lets new code be uploaded before the main program runs. Knowing how to enter bootloader mode matters when you need to program the board or recover it after a faulty sketch.
- CircuitPython
- A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
- GPIO
- General-purpose input/output pins are microcontroller pins you can set in software to read signals, switch devices on and off, or connect to peripherals. The number of GPIO pins matters because it limits how many buttons, LEDs, sensors, and other parts you can wire directly to the board.
- HID
- Human Interface Device is a USB device class used for keyboards, mice, gamepads and similar controls. If a board supports HID over USB, it can act like an input device to a computer without needing a custom driver.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- LED
- A light-emitting diode (LED) is a small electronic component that emits light when current flows through it in the correct direction. Because it only conducts one way, its polarity matters, and a through-hole LED must be soldered the correct way around to light up.
- microcontroller
- A microcontroller is a small computer on a single chip that runs a stored program and controls connected inputs and outputs such as buttons, sensors, displays and communication interfaces. In a device built around one, it is the part that executes the code and coordinates the device's behaviour.
- MicroPython
- A version of the Python programming language made to run on microcontrollers. It matters because it lets beginners write readable code to control LEDs, sensors, motors and displays without needing to start with lower-level languages.
- native USB
- Native USB means the microcontroller itself handles USB communication, rather than using a separate USB-to-serial chip. This matters for programming, debugging, and projects that need the board to act directly as a USB device.
- NeoPixel
- A type of addressable LED system where colour data is sent along a single digital data line from one LED or controller to the next. Compatibility matters because the timing and signal format must match for the lights or driver board to respond correctly.
- PWM
- Pulse Width Modulation is a way for a digital pin to simulate variable output power by switching on and off very quickly. It matters for controlling things like LED brightness, motor speed, or servo-style signals from a microcontroller pin.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- RAM
- RAM (random-access memory) is fast, temporary memory a device uses for working data while it is running; in its common volatile form, its contents are lost when power is removed. Some devices offer a mode that applies settings to RAM only, which is handy for testing changes temporarily because they are not stored permanently and disappear at power-off.
- RGB
- Short for red, green and blue, the three primary colours of light that are mixed in varying amounts to make a wide range of colours. In electronics RGB can refer to an LED or pixel that blends these three colours, or to a colour signal or interface that carries separate red, green and blue channels.
- SPI
- A fast serial communication bus often used for displays, memory cards, and sensors. It matters because SPI devices need specific pins for clock and data, plus a separate chip-select line for each device.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
- UART
- UART is a simple asynchronous serial interface that sends data over separate transmit and receive wires, usually labelled TX and RX, with both ends set to the same baud rate. It is a common way for microcontrollers and other serial devices to exchange data.
- USB-C
- USB-C is a small, reversible USB connector that can carry power, data and, on some devices, video over a single cable. The same connector can range from charging only to high-speed data, so the functions a given port actually supports vary.
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