Ameba ARDUINO: Getting Started with AMB21/AMB22 (RTL8722)


Ameba is an easy-to-program platform for developing all kind of IoT applications. AMB21/AMB22 is equipped with various peripheral interfaces, including WiFi, GPIO INT, I2C, UART, SPI, PWM, ADC. Through these interfaces, AMB21/AMB22 can connect with electronic components such as LED, switches, manometer, hygrometer, PM2.5 dust sensors, …etc.
The collected data can be uploaded via WiFi and be utilized by applications on smart devices to realize IoT implementation.


AMB21/AMB22 and Arduino Uno have similar size, as shown in the above figure, and the pins on AMB21/AMB22 are compatible with Arduino Uno.
AMB21/AMB22 uses Micro USB to supply power, which is common in many smart devices.
Please refer to the following figure and table for the pin diagram and functions.


0PB2A5 SERIAL2_RX (b)    
1PB1A4 SERIAL2_TX (b)    
2PB3A6     SWD_CLK (b)
3PB31     IR_TX (c) 
6PB29     IR_RX (c) 
8PB22    IR_RX (a) 
9PB23    IR_TX (a) 
14PA7  LOG_TX    
15PA8  LOG_RX    
16PA25 SERIAL2_RX (a) I2C_SCL (a)IR_TX (b) 
17PA26 SERIAL2_TX (a) I2C_SDA (a)IR_RX (b) 
18PB7A3 SPI1_SS   
19PB6A2  SPI1_SCLKI2C_SDA (b)  
20PB5A1 SPI1_MISOI2C_SCL (b)  
21PB4A0 SPI1_MOSI   
23PA24 SERIAL1_CTS (a) I2C1_SDA  
24PA23 SERIAL1_RTS (a) I2C1_SCL  
25PA22  SERIAL1_RX (a)    
26PA21  SERIAL1_TX (a)    

Set up developing environment

Step 1. OS environment

AMB21/AMB22 (RTL8722CSM/RTL8722DM) board currently supports Windows OS 32-bits or 64-bits, Linux OS (Ubuntu) and macOS. To have the best experiences, please use the latest version of OS.

For any Linux OS (Ubuntu) related issues, refer to

For any macOS related issues, refer to

Step 2. Installing the Driver

First, connect AMB21/AMB22 to the computer via Micro USB:


If this is the first time connects AMB21/AMB22 to computer, the USB driver for AMB21/AMB22 will be automatic installed.
If you have driver issue of connect board to computer please go to for USB driver.
Check the COM port number in Device Manager of computer:


Step 3. Set up Arduino IDE

From version 1.6.5, Arduino IDE supports third-party hardware. Therefore, we can use Arduino IDE to develop applications, and the Arduino basic examples can run on AMB21/AMB22 too. Arduino IDE can be downloaded in the Arduino website:

When the installation is finished, open Arduino IDE. To set up AMB21/AMB22 correctly in Arduino IDE, go to “File” -> “Preferences”


And paste the following URL into “Additional Boards Manager URLs” field:

Next, go to “Tools” -> “Board” -> “Boards Manager”:


The “Boards Manager” requires about 10~20 seconds to refresh all hardware files (if the network is in bad condition, it may take longer). Every time the new hardware is connected, we need to reopen the Board Manager. Find “Realtek Ameba Boards” in the list, click “Install”, then the Arduino IDE starts to download required files.


If there is GitHub downloading issue, please refer to the following link at “Download/Software Development Kit”. There are 3 sections.
1. “AMB21/AMB22_Arduino_patch1_SDK”, please select at least 1 of the SDKs. There are 5 latest released SDK options.
2. “AMB21/AMB22_Arduino_patch2_Tools”, please select according to your operation system. There are Windows, Linux and MacOS.
3. “AMB21/AMB22_Arduino_Source_Code”, this section is optional download only wants to refer the latest source code.

Download the files selected, then unzip (patch1 and patch2 are compulsory). There are “Install.doc”/“Install.pdf” for you to refer installation steps. According to your system, please run the installation tool in the “Offline_SDK_installation_tool” folder.

After the installation tool running successfully, you may open Arduino IDE and proceed to “tools” -> “Board“ -> “Boards Manager…”. Try to find “Realtek Ameba Boards” in the list, click “Install”, then the Arduino IDE starts to download required files for AMB21/AMB22.

Finally, we select board in “tools” -> “Board” -> “Ameba ARM (32-bits) Boars” -> “AMB21/AMB22 (RTL8722DM/CSM)”


Try the First Example

Step 1. Compile & Upload

Arduino IDE provides many built-in examples, which can be compiled, uploaded and run directly on the boards. Here, we take the “Blink” example as the first try.
Open “File” -> “Examples” -> “01.Basics” -> “Blink”:


Arduino IDE opens a new window with the complete sample code.

Next, we compile the sample code directly; click “Sketch” -> “Verify/Compile”


Arduino IDE prints the compiling messages in the bottom area of the IDE window. When the compilation is finished, you will get the message as following.


Afterwards, we will upload the compiled code to board.
Please make sure board is connected to computer, then click “Sketch” -> “Upload”.

The Arduino IDE will compile first then upload. Users are required to enter the upload mode of the board.
To enter upload mode, first press and hold the UART_DOWNLOAD button, then press and release the RESET button, lastly release the UART_DOWNLOAD button. There is a 5-seconds count down set as a reminder to enter the upload mode.



It is optional for users to check if the board entered the upload mode. Open serial monitor/terminal and look for “#Flash Download Start”. Note, it is normal that some serial terminals may show characters as following.


Again, during the uploading procedure the IDE prints messages. Uploading procedure takes considerably longer time (about 30 seconds to 1 minute). When upload completed, the “Done uploading” message is printed.

Step 2.Run the Blink example

In each example, Arduino not only provides sample code, but also detailed documentation, including wiring diagram, sample code explanation, technical details, …etc. These examples can be directly used on AMB21/AMB22.
So, we find the detailed information of the Blink example:

In short, this example makes LED blinks, and it uses GPIO pin 08 (refer to the pin diagram D08). Then we connect the LED and resistance as the following figure. In addition, please use a resister with suitable resistance in series between LED and GND.


Finally, press the RESET button, and you can see the LED blinking.
If you encounter any problem, please refer to Q&A.

Tool Feature

Erase Flash


• Enable: erase the image in the flash memory without uploading the current image.
• Disable: upload the user code upon compilation is finished.

“Erase Flash” is default selected as “Disable” to upload the user code.

Standard Lib Enable


• Arduino_STD_PRTINF: enable the usage of Arduino avr “stdio.h” and “#include ” when using printf
• NA: printf() is using based on standard sdk _rtl_printf()

“Standard Lib Enable” is default selected as “NA”.

Upload Speed


Selection of uploading baud rate at 1,500,000 or 921,600.

Please confirm that QQ communication software is installed