Getting Started

Add TinyUSB to your project

It is relatively simple to incorporate tinyusb to your project

  • Copy or git submodule this repo into your project in a subfolder. Let’s say it is your_project/tinyusb

  • Add all the .c in the tinyusb/src folder to your project

  • Add your_project/tinyusb/src to your include path. Also make sure your current include path also contains the configuration file tusb_config.h.

  • Make sure all required macros are all defined properly in tusb_config.h (configure file in demo application is sufficient, but you need to add a few more such as CFG_TUSB_MCU, CFG_TUSB_OS since they are passed by IDE/compiler to maintain a unique configure for all boards).

  • If you use the device stack, make sure you have created/modified usb descriptors for your own need. Ultimately you need to implement all tud descriptor callbacks for the stack to work.

  • Add tusb_init() call to your reset initialization code.

  • Call tud_int_handler() (device) and/or tuh_int_handler() (host) in your USB IRQ Handler

  • Implement all enabled classes’s callbacks.

  • If you don’t use any RTOSes at all, you need to continuously and/or periodically call tud_task()/tuh_task() function. All of the callbacks and functionality are handled and invoked within the call of that task runner.

int main(void)
  tusb_init(); // initialize tinyusb stack

  while(1) // the mainloop

    tud_task(); // device task
    tuh_task(); // host task


For your convenience, TinyUSB contains a handful of examples for both host and device with/without RTOS to quickly test the functionality as well as demonstrate how API() should be used. Most examples will work on most of the supported boards. Firstly we need to git clone if not already

$ git clone tinyusb
$ cd tinyusb

Some ports will also require a port-specific SDK (e.g. RP2040) or binary (e.g. Sony Spresense) to build examples. They are out of scope for tinyusb, you should download/install it first according to its manufacturer guide.


The hardware code is located in hw/bsp folder, and is organized by family/boards. e.g raspberry_pi_pico is located in hw/bsp/rp2040/boards/raspberry_pi_pico where FAMILY=rp2040 and BOARD=raspberry_pi_pico. Before building, we firstly need to download dependencies such as: MCU low-level peripheral driver and external libraries e.g FreeRTOS (required by some examples). We can do that by either ways:

  1. Run tools/ {FAMILY} script to download all dependencies for a family as follow. Note: For TinyUSB developer to download all dependencies, use FAMILY=all.

$ python tools/ rp2040
  1. Or run the get-deps target in one of the example folder as follow.

$ cd examples/device/cdc_msc
$ make BOARD=raspberry_pi_pico get-deps

You only need to do this once per family. Check out complete list of dependencies and their designated path here


To build example, first change directory to an example folder.

$ cd examples/device/cdc_msc

Then compile with make BOARD={board_name} all , for example

$ make BOARD=raspberry_pi_pico all

Note: some examples especially those that uses Vendor class (e.g webUSB) may requires udev permission on Linux (and/or macOS) to access usb device. It depends on your OS distro, typically copy 99-tinyusb.rules and reload your udev is good to go

$ cp examples/device/99-tinyusb.rules /etc/udev/rules.d/
$ sudo udevadm control --reload-rules && sudo udevadm trigger

RootHub Port Selection

If a board has several ports, one port is chosen by default in the individual file. Use option PORT=x To choose another port. For example to select the HS port of a STM32F746Disco board, use:

$ make BOARD=stm32f746disco PORT=1 all

Port Speed

A MCU can support multiple operational speed. By default, the example build system will use the fastest supported on the board. Use option SPEED=full/high e.g To force F723 operate at full instead of default high speed

$ make BOARD=stm32f746disco SPEED=full all

Size Analysis

First install linkermap tool then linkermap target can be used to analyze code size. You may want to compile with NO_LTO=1 since -flto merges code across .o files and make it difficult to analyze.

$ make BOARD=feather_nrf52840_express NO_LTO=1 all linkermap


To compile for debugging add DEBUG=1, for example

$ make BOARD=feather_nrf52840_express DEBUG=1 all


Should you have an issue running example and/or submitting an bug report. You could enable TinyUSB built-in debug logging with optional LOG=. LOG=1 will only print out error message, LOG=2 print more information with on-going events. LOG=3 or higher is not used yet.

$ make BOARD=feather_nrf52840_express LOG=2 all


By default log message is printed via on-board UART which is slow and take lots of CPU time comparing to USB speed. If your board support on-board/external debugger, it would be more efficient to use it for logging. There are 2 protocols:

  • LOGGER=rtt: use Segger RTT protocol

    • Cons: requires jlink as the debugger.

    • Pros: work with most if not all MCUs

    • Software viewer is JLink RTT Viewer/Client/Logger which is bundled with JLink driver package.

  • LOGGER=swo: Use dedicated SWO pin of ARM Cortex SWD debug header.

    • Cons: only work with ARM Cortex MCUs minus M0

    • Pros: should be compatible with more debugger that support SWO.

    • Software viewer should be provided along with your debugger driver.

$ make BOARD=feather_nrf52840_express LOG=2 LOGGER=rtt all
$ make BOARD=feather_nrf52840_express LOG=2 LOGGER=swo all


flash target will use the default on-board debugger (jlink/cmsisdap/stlink/dfu) to flash the binary, please install those support software in advance. Some board use bootloader/DFU via serial which is required to pass to make command

$ make BOARD=feather_nrf52840_express flash
$ make SERIAL=/dev/ttyACM0 BOARD=feather_nrf52840_express flash

Since jlink can be used with most of the boards, there is also flash-jlink target for your convenience.

$ make BOARD=feather_nrf52840_express flash-jlink

Some board use uf2 bootloader for drag & drop in to mass storage device, uf2 can be generated with uf2 target

$ make BOARD=feather_nrf52840_express all uf2

IAR Support

Use project connection

IAR Project Connection files are provided to import TinyUSB stack into your project.

  • A buldable project of your MCU need to be created in advance.

    • Take example of STM32F0:

      • You need stm32l0xx.h, startup_stm32f0xx.s, system_stm32f0xx.c.

      • STM32L0xx_HAL_Driver is only needed to run examples, TinyUSB stack itself doesn’t rely on MCU’s SDKs.

  • Open Tools -> Configure Custom Argument Variables (Switch to Global tab if you want to do it for all your projects)

    Click New Group …, name it to TUSB, Click Add Variable …, name it to TUSB_DIR, change it’s value to the path of your TinyUSB stack, for example C:\tinyusb

Import stack only

  1. Open Project -> Add project Connection ..., click OK, choose tinyusb\tools\iar_template.ipcf.

Run examples

  1. (Python3 is needed) Run to generate .ipcf files of examples:

    cd C:\tinyusb\tools
  2. Open Project -> Add project Connection …, click OK, choose tinyusb\examples\(.ipcf of example). For example C:\tinyusb\examples\device\cdc_msc\iar_cdc_msc.ipcf

Native CMake support (9.50.1+)

With 9.50.1 release, IAR added experimental native CMake support (strangely not mentioned in public release note). Now it’s possible to import CMakeLists.txt then build and debug as a normal project.

Following these steps:

  1. Add IAR compiler binary path to system PATH environment variable, such as C:\Program Files\IAR Systems\Embedded Workbench 9.2\arm\bin.

  2. Create new project in IAR, in Tool chain dropdown menu, choose CMake for Arm then Import CMakeLists.txt from chosen example directory.

  3. Set up board option in Option - CMake/CMSIS-TOOLBOX - CMake, for example -DBOARD=stm32f439nucleo -DTOOLCHAIN=iar, Uncheck ‘Override tools in env’.

  4. (For debug only) Choose correct CPU model in Option - General Options - Target, to profit register and memory view.