Guide to USB development resources on STM32

Gyessine · ‎2025-05-06

Introduction

This article gives you the key information you need to dive into USB development on STM32. It mentions various resources, including training (MOOCs), articles, and application notes, that can help understand USB theory and hardware implementation.

1. USB theory

1.1 Starting with the fundamentals

To dive deep into USB theory and understand the fundamentals, check the following resources:

USB protocol basic: Watch the first 14 minutes of the STM32 USB training introduction and read the USB introduction PDF
Endpoints and data packets structure: Endpoints are specific channels within a USB device. For data transfer, data packets are structured units of information transmitted through these endpoints

Watch the STM32 USB transfers training and read the USB transfers PDF. You can also read the "How to select suitable endpoints for your STM32 USB application" article that helps you to know how to choose the necessary number of endpoints.

USB descriptors: We recommend watching the STM32 USB descriptors training and reading the USB descriptors PDF
USB STM32 standard class overview: To identify which class you need, watch the STM32 USB standard class training and read the USB standard class overview PDF

You can also read the ST Wiki: USB protocol basics from section 1.0 to 1.15.

For more technical information related to USB, see the USB specification and USB class specifications that can be downloaded from https://www.usb.org/developers

1.2 USB hardware implementation on an STM32

USB requires specific hardware components and principals to function correctly, and it is essential to understand them such as:

USB states: Watch the STM32 USB training introduction and read the USB introduction PDF

All the points listed down below are covered in STM32 USB hardware design training in a basic way. Additionally, in the ST USB hardware design PDF.

Internal and external clocks

Check the relevant datasheet for your product. For more information, check section 2.4 "Clock" in AN4879.

Internal and external PHYs required for HS and internal PHYs

For this point, you can also check this article about ULPI compatibility or section 3.3 OTG applications through embedded PHY to 3.5 USB applications through the embedded OTG_HS PHY of AN4879.

Hardware architecture for DEVICE and HOST mode
ESDs and concept of VBUS sensing

Check this article for more specific overview or check section 2.6 "VBUS sensing detection point" and section 2.3 "Protection against ESD and EMI" in AN4879.

To see STM32 products USB specifications, you can refer to the section 2, “USB on STM32 products” in AN4879.

Refer to specific application notes and datasheets for detailed hardware implementation guidance like the application notes for H5, F7, H7R/S, and H72x/H73x.

Application notes are titled under the name: “Getting started with STM32Xx MCU hardware development”.

To dive deeper, refer to each product’s datasheets, reference manual, application note, and schematics (noted as MBxx example: MB997 for F407G-Disco.)

1.3 ST USB middleware

ST USB middleware provides libraries and tools to facilitate USB device and host functionality on STM32 microcontrollers. It is composed mainly of the device library and host library. We recommend referring to the links in section 1.3.1 and 1.3.2.

1.3.1 Device mode

For a general understanding of device mode, watch the STM32 USB device library training, read the fifth section in the wiki and view the STM32 USB device library PDF.

For more in-depth review, check UM1734, sixth point USB device library of UM1021 or UM0424 for USB-FS demos.

If you are still searching for helpful resources on the subject, here are some extra links that might help:

DFU class: AN3156 for DFU basic commands explanation
Audio class: UM2195

1.3.2 Host mode

You can watch the STM32 USB host library training, read the "USB host library overview" in the ST wiki, and explore the STM32 USB host library PDF.

For a deep explanation, check the section 7. "USB host library" in UM1021.

2. Projects and application notes

2.1 One class projects

Almost each board has a simple example in its cube firmware for certain USB classes in both device and host mode. To access them, you just need to follow this path and open the project in your toolchain.

C:\Users\xxxxxx\STM32Cube\Repository\STM32Cube_FW_xx_Vx.xx.x\Projects\xxxxxxxxx\Applications\

This is the default path, but it may change if you chose another location for installing the firmware.

Other than that, there are projects and guidelines available.

Class	Mode	Projects/AN’s	Details
HID	Device	Mouse project	Check your board firmware or visit this lab
		Custom device	How to implement a custom device project lab and check USB HID articles part 1 and part 2
		Other basics	Section 6.10.2 USB human interface device example of UM1021
	Host	Mouse project	Check your board firmware or visit this lab
	Host	Display message	Section 7.10.2 "USB HID host" example in UM1021
CDC	Device	Receive and transmit project	Check your firmware if you have an evaluation board, or follow this lab
		Basics	Section 6.10.5 "USB virtual com port (VCP) device" example in UM1021
		How to set line coding	Check out this "How to set USB CDC line coding" article
	Host	Basic	Check your firmware if you have evaluation board or visit this LAB
DFU	Device	Enable DFU mode	Check your firmware or follow the device mode hands-on
		Basics	Check AN3156 for DFU basic commands
		Basics	Section 6.10.4 "USB device firmware upgrade example" in UM1021
		How to modify DFU firmware examples	Check this article
		How to jump to system bootloader	Check this article
		Open bootloader	Check this article
		Dual bank demo	Check this GitHub example (H5 board)
	Host	Basics	Check your firmware or follow the host mode hands-on
MSC	Device	Mass storage	Check your firmware or follow the device mode lab
		Basics	Section 6.10.1 "USB mass storage device example" in UM1021
		Bootloader USB mass storage	Check this GitHub example for the STM32G0
	Host	Basics	Check your firmware or follow the device mode lab
	Host	Basics	Section 7.10.1 "USB mass storage host example" in UM1021
AUDIO	Device	Basics	Section 6.10.6 "USB audio device example" in UM1021
AUDIO	Device	Bridge example	AN4711 for the STM32F0

2.2 USB + DMA

How to set up USB DMA controller with STM32H7 devices article

2.3 Composite classes projects

How to implement the USB device composite class (DFU + HID) article and its associated project
How to implement USB device composite class in STM32H5 microcontrollers (HID + CDC) tutorial and project
How to implement USB device composite class DUAL CDC article
For STM32H7 boards, you can download this branch of firmware for composite examples

2.4 USB + Other peripherals

How to run Bluetooth® Low Energy P2P server with USB CDC on STM32WB article part 1 and part 2.

3. STM32 Legacy middleware articles

How to use classic USB device middleware with the new STM32 families article

This tutorial explains how to import and use the legacy STMicroelectronics USB middleware in the new STM32 lines to implement a CDC class for opening a virtual COM port.

How to implement USB Communication Device Class (CDC) article

Note that some products are native STM32 classic middleware but there are some products that have also available USBX Azure package like H7, H7RS, L5, WB, G4, G0, F7, F4, WL, and L4.

4. STM32 USBX Azure package articles

How to implement the USB device composite class using the Azure hands-on and associated project
How to implement the USB device CDC class using the Azure hands-on
How to implement USB host using the Azure package hands-on
How to implement USBX in standalone mode article
Dual CDC project with USBX stack GitHub link

Some packages use USBX stack natively. Refer to the classic middleware accordingly.

5. FAQ and common errors

USB device not recognized
How to set USB CDC line coding
FAQ: Configuring the VDD50USB and VDD33USB pins on STM32H7 when not using USB
FAQ: Possible communication failure between STLINK and recent computers
Section 5. "Frequently asked questions" regarding USB hardware in AN4879
Section 8. "Frequently asked questions" regarding USB OTG in UM1021
Section 7. "Frequently asked questions" regarding device library in UM1734

Conclusion

Overall, the article provides a thorough guide for USB development on STM32. It includes various resources such as MOOCs, articles, and application notes.

All useful links are directly accessible.

Ahmet Yasin CİVAN · ‎2025-05-15

Thank you so much for sharing this comprehensive guide to USB development resources on STM32! This is an invaluable resource for both beginners and experienced developers working with STM32 microcontrollers. The detailed breakdown of available documentation, example projects, and tools will definitely save many hours of searching across different sources. I particularly appreciate how well-organized the information is, making it easy to find exactly what's needed for specific USB implementations. This guide will be a great reference for my future STM32 projects.