# Adafruit CH552 QT Py

## Overview

![](https://cdn-learn.adafruit.com/assets/assets/000/129/843/medium800thumb/adafruit_products_5960-00.jpg?1715002862)

What a cutie pie! Or is it... a QT Py? This diminutive dev board comes with a throwback processor - an 8-bit 8051! This tiny core is a big change from something like the [ESP32-S3 QT Py with two 240MHz 32-bit cores](https://www.adafruit.com/product/5700), but there are lots of folks interested in the [CH552](https://www.wch-ic.com/products/CH552.html) and, given the smol size, it is a nice matchup for a smol board.

![](https://cdn-learn.adafruit.com/assets/assets/000/129/844/medium800/adafruit_products_5960-04.jpg?1715003063)

[The CH552 is an 'enhanced' E8051 core microcontroller](https://www.wch-ic.com/products/CH552.html), compatible with the MCS51 instruction set but with 8~15 times faster instruction execution speed. You can run this core at 16MHz and 3.3V logic, and it's got built-in 16K program FLASH memory and, 256-byte internal RAM plus 1K-byte internal xRAM (xRAM supports DMA.

It's also got some cute tricks up its sleeve, like 4 built-in ADC channels, capacitive touch support, 3 timers / PWM channels, hardware UART, SPI, and a full-speed USB device controller. The last one means it can act like a native USB device such as CDC serial or mouse/keyboard HID.

![](https://cdn-learn.adafruit.com/assets/assets/000/129/845/medium800/adafruit_products_5960-02.jpg?1715003120)

If you're interested in playing with this chip, we've wrapped it up in a QT Py format. The pinout and shape is [Seeed Xiao](https://wiki.seeedstudio.com/Seeeduino-XIAO/) compatible, with castellated pads so you can solder it flat to a PCB. It comes with [our favorite connector - the STEMMA QT](http://adafruit.com/stemma), a chainable I2C port that can be used with [any of our STEMMA QT sensors and accessories](https://www.adafruit.com/category/620). We also added an RGB NeoPixel and both a reset button and 'bootloader enter' button.

![](https://cdn-learn.adafruit.com/assets/assets/000/129/846/medium800/adafruit_products_5960-03.jpg?1715003193)

 **Please note! This is a minimal 8-bit microcontroller, and it definitely does _not_ run CircuitPython or Micropython. It also doesn't _really_ run Arduino.** [There's an Arduino 'board support package'](https://github.com/DeqingSun/ch55xduino) we recommend, but the compiler is for C not C++, which means you _cannot use any Arduino libraries_. It's very very bare-bones and for [hacking/experimenting with this '40 cent chip'](https://hackaday.com/2023/03/03/all-the-usb-you-can-do-with-a-ch552/).

- It is the same size, form-factor, and pinout as the Seeed Xiao.
- **USB Type C connector** - [If you have only Micro B cables, this adapter will come in handy](https://www.adafruit.com/product/4299)!
- **CH552 8-bit 8051 ** microcontroller core with 3.3V power/logic. Internal 16 MHz oscillator.
- Native USB
- **Built in RGB NeoPixel LED**
- **10 GPIO pins:**
  - 4x 8-bit analog inputs on A0, A1, A2, and A3
  - 3 x PWM outputs
  - I2C port with STEMMA QT plug-n-play connector
  - Hardware UART
  - Hardware SPI
  - 4 x Capacitive Touch with no additional components required, on A0-A3 pins

- 3.3V regulator with [**600mA peak output**](https://www.diodes.com/assets/Datasheets/AP2112.pdf)
- **Reset switch and bootloader** for starting your project code over or entering USB ROM bootloader mode
- **Really really small**

- [Next Page](https://learn.adafruit.com/adafruit-ch552-qt-py/pinouts.md)

## Primary Products

### Adafruit CH552 QT Py - 8051 Dev Board with STEMMA QT

[Adafruit CH552 QT Py - 8051 Dev Board with STEMMA QT](https://www.adafruit.com/product/5960)
What a cutie pie! Or is it... a QT Py? This diminutive dev board comes with a throwback processor - an 8-bit 8051! This tiny core is a big change from something like the the [ESP32-S3 QT Py with two 240MHz 32-bit cores](https://www.adafruit.com/product/5700), but there's lots of...

In Stock
[Buy Now](https://www.adafruit.com/product/5960)
[Related Guides to the Product](https://learn.adafruit.com/products/5960/guides)

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