Lightweight USB Device Stack

• Lightweight and fast
• Event-driven process workflow
• Completely separated USB hardware driver and usb core
• Easy to use.

Requirements

• CMSIS V4 or CMSIS V5.
• stm32.h STM32 universal header

All requirements can be downloaded into a directory specified in environment variable CMSIS using make cmsis command.

Supported hardware

MCU Series	Features	Driver	File
STM32L0x2 STM32L0x3 STM32F070 STM32F0x2 STM32F0x8	Doublebuffered[2] 8[1] endpoints BC1.2	usbd_devfs	usbd_stm32l052_devfs.c
		usbd_devfs_asm	usbd_stm32l052_devfs_asm.S
STM32L4x2 STM32L4x3 STM32G4 series	Doublebuffered[2] 8[1] endpoints BC1.2	usbd_devfs	usbd_stm32l433_devfs.c
		usbd_devfs_asm	usbd_stm32l052_devfs_asm.S
STM32L1xx	Doublebuffered[2] 8[1] endpoints	usbd_devfs	usbd_stm32l100_devfs.c
		usbd_devfs_asm	usbd_stm32l100_devfs_asm.S
STM32F102 STM32F103 STM32F302 STM32F303 STM32F373	Doublebuffered[2] External DP pullup 8[1] endpoints	usbd_devfs	usbd_stm32f103_devfs.c
		usbd_devfs_asm	usbd_stm32f103_devfs_asm.S
STM32WB55	Doublebuffered[2] External DP pullup 8[1] endpoints	usbd_devfs	usbd_stm32wb55_devfs.c
STM32L4x5 STM32L4x6	Doublebuffered 6 endpoints BC1.2 VBUS detection	usbd_otgfs	usbd_stm32l476_otgfs.c
STM32F401 STM32F411	Doublebuffered 4 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32f429_otgfs.c
STM32F4x5 STM32F4x7 STM32F4x9	Doublebuffered 4 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32f429_otgfs.c
	Doublebuffered 6 endpoints VBUS detection SOF output	usbd_otghs	usbd_stm32f429_otghs.c
STM32F105 STM32F107	Doublebuffered 4 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32f105_otgfs.c
STM32F4x6 STM32F7	Doublebuffered 6 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32f446_otgfs.c
	Doublebuffered 9 endpoints VBUS detection SOF output	usbd_otghs	usbd_stm32f446_otghs.c
STM32H743	Doublebuffered 6 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32h743_otgfs.c

1. Single physical endpoint can be used to implement

• one bi-directional/single-buffer logical endpoint (CONTROL)
• one uni-directional/double-buffer logical endpoint (BULK OR ISOCHRONOUS)
• two uni-directional/single-buffer logical endpoints (BULK OR INTERRUPT)

2. At this moment BULK IN endpoint can use both buffers, but it is not real doublebuffered.

3. Tested with STM32L052K8, STM32L100RC, STM32L476RG, STM32F072C8, STM32F103C8, STM32F103CB, STM32F303CC, STM32F303RE, STM32F429ZI, STM32F105RBT6, STM32F107VCT6, STM32L433CCT6, STM32F070CBT6, STM32G431RB, STM32F411CEUx, STM32F405RG, STM32F446RE, STM32F373CC, STM32L053R8, GD32F103C8T6, STM32F745VE, STM32F401CE, STM32H743. See hardware.md for details.

Don't copy-paste the startup code from the demo without considering RCC and USB clock requirements.

The HSI oscillator usually does not meet the timing requirements for USB and may cause performance loss and a high error rate.

Implemented definitions for classes

1. USB HID based on Device Class Definition for Human Interface Devices (HID) Version 1.11
2. USB DFU based on USB Device Firmware Upgrade Specification, Revision 1.1
3. USB CDC based on Class definitions for Communication Devices 1.2
4. USB TMC based on USB Device Test and Measurement Class Specification, Revision 1.0

Using makefile

• to build library module

make module MODULE=path/module.a DEFINES="mcu specified defines" CFLAGS="cpu specified compiler flags"

• to build demo

make bluepill program
make stm32l052x8

• to get a help

make help

Default values:

Variable	Default Value	Means
CMSIS	./CMSIS	path to CMSIS root folder
CMSISDEV	$(CMSIS)/Device	path to CMSIS device folder
CMSISCORE	$(CMSIS)/CMSIS/Include $(CMSIS)/CMSIS/Core/Include	path to CMSIS core headers
MCU	stm32l100xc	MCU selection for demo project
CFLAGS	-mcpu=cortex-m3 -mfloat-abi=soft	MCU specified compiler flags
DEFINES	STM32L1 STM32L100xC	MCU specified defines
STPROG_CLI	~/STMicroelectronics/STM32Cube/STM32CubeProgrammer/bin/STM32_Programmer_CLI	Path to the ST Cube Programmer CLI
OPTFLAGS	-Os	Code optimization flags

Useful Resources

1. USB Implementers Forum official site
2. USB Made Simple
3. LUFA - the Lightweight USB Framework for AVRs.
4. Open Source ARM cortex m microcontroller library