AI-WB2 and XIAO RP2040 Combo

`Ai-Thinker (#notsponsored) should be quite well known to many makers as a company that manufactured and designs many of the modules that we use in our projects. We, MakerIoT2020, definitely make use of quite a few of their products, like the RA-02, as well as their ESP32-S module.

A few months ago, I got the opportunity to play with one of their newest projects, the AI-WB2, which is based on the BL602 Risc-V Chip. After a very very bumpy ride, mainly due to the chip being quite new, and documentation being virtually nonexistent in the English language, I decided to take a step back, and stop trying to reinvent the wheel 🙂 Afterall, I don’t want to use Apache NuttX or a similar RTOS for every project, as the thought of having to write almost all of the different required components from scratch, does not really appeal to me. especially as the SDK is in Chinese, and the English version of it is a bit patchy, to say the least…

This made me quite a bit frustrated, at least until I decided to change my thinking, and take a look at the stock AT command set that comes shipped on the modules from the factory… While excellent for use as a WiFi modem, it did not seem to allow any access to any of the GPIO on the WB-AI2 module… But wait… is that really a problem? No… Let me tell you why…

I also have a few XIAO Modules ( the RP2040 and SAMD21 ) lying around, and those do not have any connectivity options onboard…

A few very quick tests later, It was clear that the AI-WB2 will be a very compact
WiFi as well as BTLE connectivity solution for these XIAO modules, and, If I design with the future in mind, the GPIO pins of the AI-WB2 module can also become useable to me as well… once the firmware and SDK gets more accessible..

What followed from this is a very basic prototype PCB, with the XIAO RP2040 as the main processor, and the AI-WB2-12F as a “connectivity co-processor”, meaning that all communications functions will be offloaded to the AI-WB2 and the results of those, sent back to the XIAO for processing…

This in itself presents quite a few challenges, especially on the communications handling, and using the second UART port, which is currently not possible with the official Arduino Core for the RP2040… Luckily, the XIAO RP2040 uses an alternative core, that supports the second UART port quite well …

What is on the PCB?

AI-WB2-12F XIAO Combo

The Top Section of the PCB is dedicated to the AI-WB2-12F and its supporting components, including a flash and reset button. The GPIO for the WB2-12F is broken out onto H1.

At the right, below H1, is a series of jumpers, connecting the Xiao RP2040 and WB2-12-F Uart ports, or, alternatively, connecting the XIAO Rp2040 to the pin headers at the side of the PCB.

The rest of the PCB is dedicated to the Xiao RP2040 or Xiao SAMD21 module, with its supporting circuitry, and a dedicated Reset button for the SAMD21 module ( also works for the RP2040)

The board is powered with 5v DC through a dedicated header at the left bottom. This directly powers the Xiao and indirectly powers the WB2-12-F through a 3.3v LDO Regulator. Please note that although the Xiao is powered via 5v, the GPIO pins are all 3.3v logic!

The Schematic and PCB


PCB Layout


MQTT Connection on the AI-WB2-12F

AI-Thinker Example

The full AT command set example is available here

For the Xiao RP2040, like I used, it is possible to use the second UART to connect to the AI-WB2 chip.

As I am still not completely done with my development, I will not release the full code at this moment.

I have also been informed by AI-Thinker that a new version of the AT-command firmware is available that will allow using the GPIO on the AI-WB2 via AT Commands. I am currently investigating that new version, and that is also a big reason for not releasing any code at this stage.


The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.


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Carrier board for SEEEDuino XIAO

These days, Makers have access to quite a few different microprocessors for use in their projects. Most of them can be found on development boards of some sort, but not all are in a convenient size. The reason for this is that most of these development boards were designed with a breadboard in mind, and then after your prototype is done, you are required to design a PCB and place the specific processor and its supporting components onto this custom PCB…

Many makers choose to skip this step, either choosing to keep the project on the breadboard, or place the entire development module onto a piece of stripboard or similar, and then place their supporting components and sensors around that.

This is where the SEEED XIAO is different. It comes in a thumb-nail-sized package and can be used on the breadboard or directly placed onto a PCB via either pin headers or if you want access to all of its features, SMD pads.


In this build, I decided to design a generic carrier board, that will accept most of the XIAO RP2040 or the XIAO SAMD21

I have also included a small prototype area on the PCB, so that Makers can easily transfer their existing XIAO projects onto a semi-custom PCB, without having to design their own.

I have also addressed a problem area, especially with the XIAO SAMD21, it has no onboard reset button, only two tiny pads, by including a reset button for ease of use.

The PCB is in Arduino Uno form factor, and also provides headers to power it from an external 5v DC supply. Please note that the prototyping area has a 3.3v power rail, – due to the fact that all of the XIAO GPIO are limited to 3.3v anyway -. This power rail is powered directly from the XIAO 3.3v output, and the current is limited as per the specifications of the XIAO module that you are using.

Hardware Specifications – SEEEDuino XIAO

Hardware specifications and comparison

ProcessorESP32-C3 32-bit RISC-V @160MHzSAMD21 M0+@48MHzRP2040 Dual-core M0+@133MhznRF52840 M4F@64MHznRF52840 M4F@64MHz
Wireless ConnectivityWiFi and Bluetooth 5 (LE)N/AN/ABluetooth 5.0/BLE/NFCBluetooth 5.0/BLE/NFC
Memory400KB SRAM, 4MB onboard Flash32KB SRAM 256KB FLASH264KB SRAM 2MB onboard Flash256KB RAM, 1MB Flash 2MB onboard Flash256KB RAM,1MB Flash 2MB onboard Flash
Built-in SensorsN/AN/AN/AN/A6 DOF IMU (LSM6DS3TR-C), PDM Microphone
PWM/Analog Pins11/411/1111/411/611/6
Onboard ButtonsReset/ Boot ButtonN/AReset/ Boot ButtonReset ButtonReset Button
Onboard LEDsCharge LEDN/AFull-color RGB/ 3-in-one LED3-in-one LED/ Charge LED3-in-one LED/ Charge LED
Battery Charge ChipBuilt-inN/AN/ABQ25101BQ25101
Programming LanguagesArduinoArduino/ CircuitPythonArduino/ MicroPython/ CircuitPythonArduino/ MicroPython/ CircuitPythonArduino/ MicroPython/ CircuitPython



The PCB for this project has been manufactured at PCBWay.
Please consider supporting them if you would like your own copy of this PCB, or if you have any PCB of your own that you need to have manufactured.


More Pictures