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This project provides some examples of developing applications using C/C++ in a Linux environment, which can be run on the Milk-V Duo
device.
You can also use Ubuntu installed in a virtual machine, Ubuntu installed via WSL on Windows, or Ubuntu-based systems using Docker.
-
Install the tools that compile dependencies.
sudo apt-get install wget git make
-
Get example source code
git clone https://github.com/milkv-duo/duo-examples.git
-
Prepare compilation environment
cd duo-examples source envsetup.sh
The first time you source it, the required SDK package will be automatically downloaded, which is approximately 180MB in size. Once downloaded, it will be automatically extracted to the
duo-examples
directory with the nameduo-sdk
. When source it next time, if the directory already exists, it will not be downloaded again. -
Compile testing
Take hello-world as an example, enter the hello-world directory and execute make
cd hello-world make
After the compilation is successful, send the generated
helloworld
executable program to the Duo device through the network port or the RNDIS network. For example, the RNDIS method supported by the default firmware, Duo’s IP is 192.168.42.1, the user name isroot
, and the password ismilkv
scp helloworld [email protected]:/root/
After sending successfully, run ./helloworld in the terminal logged in via ssh or serial port, and it will print
Hello, World!
[root@milkv]~# ./helloworld Hello, World!
At this point, our compilation and development environment is ready for use.
You can simply copy existing examples and make necessary modifications. For instance, if you need to manipulate a GPIO, you can refer to the blink
example. LED blinking is achieved by controlling the GPIO's voltage level. The current SDK utilizes the WiringX library for GPIO operations, which has been adapted specifically for Duo. You can find the platform initialization and GPIO control methods in the blink.c
code for reference.
- Create your own project directory called
my-project
. - Copy the
blink.c
andMakefile
files from theblink
example to themy-project
directory. - Rename
blink.c
to your desired name, such asgpio_test.c
. - Modify the
Makefile
by changingTARGET=blink
toTARGET=gpio_test
. - Modify
gpio_test.c
to implement your own code logic. - Execute the
make
command to compile. - Send the generated
gpio_test
executable program to Duo for execution.
Note:
- Creating a new project directory is not mandatory to be placed within the
duo-examples
directory. You can choose any location based on your preference. Before executing themake
compilation command, it is sufficient to load the compilation environment from theduo-examples
directory (source /PATH/TO/duo-examples/envsetup.sh). - Within the terminal where the compilation environment (envsetup.sh) is loaded, avoid compiling Makefile projects for other platforms such as ARM or X86. If you need to compile projects for other platforms, open a new terminal.
A simple example that doesn't interact with Duo peripherals, only prints the output "Hello, World!" to verify the development environment.
This example demonstrates how to control an LED connected to a GPIO pin. It uses the WiringX library to toggle the GPIO pin's voltage level, resulting in the LED blinking.
The blink.c
code includes platform initialization and GPIO manipulation methods from the WiringX library.
To test the blink
example, which involves LED blinking, you need to disable the script responsible for the automatic LED blinking on the default firmware of Duo. In the Duo terminal, execute the following command:
mv /mnt/system/blink.sh /mnt/system/blink.sh_backup && sync
This command renames the LED blinking script. After restarting Duo, the LED will no longer blink.
Once you have finished testing the blink
program implemented in C, if you want to restore the LED blinking script, you can rename it back using the following command and then restart Duo:
mv /mnt/system/blink.sh_backup /mnt/system/blink.sh && sync
App | Description |
---|---|
bmp280_i2c | By connecting the temperature and pressure sensor BMP280 through the I2C interface, you can read the current temperature and pressure values. |
vl53l0x_i2c | Read the Time of Flight sensor VL53L0X module to get the measured distance. |
ssd1306_i2c | Displaying strings on SSD1306 OLED display via I2C interface. |
adxl345_i2c | Read the acceleration data obtained by ADXL345 through the I2C interface, once every 1 sencond. |
lcm1602_i2c | Display string on 1602 LCD screen via I2C interface. |
lcm2004_i2c | Display string on 2004 LCD screen via I2C interface. |
tcs34725_i2c | Read the TCS34725 color sensor through the I2C interface and output the obtained data. |
App | Description |
---|---|
max6675_spi | Connect the K-type thermocouple measurement module MAX6675 through the SPI interface to measure the temperature on the current sensor. |
rc522_spi | Connect the RC522 RFID reading and writing module through the SPI interface, read the card ID and type and output it to the screen. |
This example enables the CV180x 12bit resolution analog-digital converter module, called SARADC. /adc/ has two examples to run the module, first is an sh script and the other one is C source file, which can be easy compiled with TinyCC on Duo board.
The SARADC utilization reference is the CV180x CV181x Peripheral Drive Operation Guide.