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lbuild module: modm:tinyusb

TinyUSB is an open-source cross-platform USB Host/Device stack for embedded system, designed to be memory-safe with no dynamic allocation and thread-safe with all interrupt events are deferred then handled in the non-ISR task function.

This module provides a autogenerated port for TinyUSB, which includes the correct interrupt mapping, a serial number based on the UID of the device, as well as remapping the assertions of TinyUSB.

Autogeneration of USB Descriptors

You can select the device classes you want to use via the modm:tinyusb:config list option:

  • device.cdc: Serial connection (uses two endpoints!)
  • device.msc: Mass Storage class.
  • device.midi: MIDI device.
  • device.vendor: WebUSB device.
  • device.dfu: DFU (runtime only).

Note that you can add multiple devices at the same time, as long as there are enough endpoints and USB RAM available:

<!-- Using the CDC and MSC classes together -->
<option name="modm:tinyusb:config">device.cdc,device.msc</option>
<!-- Using two CDC ports! -->
<option name="modm:tinyusb:config">device.cdc,device.cdc</option>

modm will generate the USB descriptors automatically for the set of device classes you've chosen. You can then implement your app via TinyUSB callbacks.

Manual USB Descriptors

If you leave the modm:tinyusb:config option empty, no descriptors are generated, so you can implement them yourself. Note that you must also manually depend on the device classes you want to implement:


Initializing USB

The modm:platform:usb module provides the correct way of initializing the USB peripheral, however, you must connect the right signals too:

// USB is timing-sensitive, so prioritize the IRQs accordingly

// For Device-Only USB implementations, this is enough
Usb::connect<GpioA11::Dm, GpioA12::Dp>();

// But for On-The-Go (OTG) USB implementations, you need more:
Usb::connect<GpioA11::Dm, GpioA12::Dp, GpioA10::Id>();
// Enable hardware Vbus sensing on GpioA9 (this can be tricky to get right!)

Note that depending on your specific hardware setup, you may need to fiddle around to find the right VBus sensing mechanism.

USB shares resources with CAN

Note that on STM32F1 and STM32F3 the USB interrupts and RAM are shared with CAN, thus there are conflicts in IRQ definitions as well as resource limitions in hardware. On some STM32F3, the USB IRQs can be remapped, this is done automatically by our port.

Debugging TinyUSB

Since we've made it so easy to add multiple device classes, it's also easy to run out of endpoints or RAM. Therefore we reroute TinyUSBs assertions to modm_assert, so make sure you have implemented the modm_abandon handler! See the modm:architecture:assert module for details.

A TinyUSB assertion failure in release mode is fairly cryptic:

Assertion 'tu' failed!

If you run this again in debug mode, you'll note a much more detailed assertion description. In this example you've exhaused the number of endpoints:

Assertion 'tu' failed!
  modm/ext/tinyusb/portable/st/synopsys/dcd_synopsys.c:524 -> "epnum < 4U"

To trace the TinyUSB core, you can add CFG_TUSB_DEBUG=2 to your CPP flags and the output will be forwarded to MODM_LOG_DEBUG.

<collect name="modm:build:cppdefines">CFG_TUSB_DEBUG=2</collect>

This module is only available for sam, stm32{f0,f1,f2,f3,f4,f7,g4,l1,l4}.



Endpoint Configuration

Default: []
Inputs: [device.cdc, device.dfu, device.midi, device.msc, device.vendor]
Input Dependency: device.cdc -> modm:tinyusb:device:cdc
Input Dependency: device.dfu -> modm:tinyusb:device:dfu
Input Dependency: device.midi -> modm:tinyusb:device:midi
Input Dependency: device.msc -> modm:tinyusb:device:msc
Input Dependency: device.vendor -> modm:tinyusb:device:vendor


USB Port Speed

This option is only available for stm32{f2,f4,f7}.

Default: full
Inputs: [full, high]
Input Dependency: full -> modm:platform:usb:fs
Input Dependency: high -> modm:platform:usb:hs



modm_tinyusb modm: tinyusb

modm_architecture_interrupt modm: architecture: interrupt


modm_cmsis_device modm: cmsis: device


modm_platform_usb modm: platform: usb


modm_platform_usb_fs modm: platform: usb: fs


modm_platform_usb_hs modm: platform: usb: hs


modm_tinyusb_device_cdc modm: tinyusb: device: cdc


modm_tinyusb_device_dfu modm: tinyusb: device: dfu


modm_tinyusb_device_midi modm: tinyusb: device: midi


modm_tinyusb_device_msc modm: tinyusb: device: msc


modm_tinyusb_device_vendor modm: tinyusb: device: vendor


Limited availability: Check with 'lbuild discover' if this module is available for your target!