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.
• Device peripheral access layer header files for STM32. See Vendor Template for details.
• stm32.h STM32 universal header

Supported hardware

MCU Series	Features	Driver	File
STM32L0x2 STM32L0x3 STM32L4x2 STM32L4x3 STM32F0x2 STM32F0x8	Doublebuffered 8 endpoints BC1.2	usbd_devfs	usbd_stm32l052_devfs.c
		usbd_devfs_asm	usbd_stm32l052_devfs_asm.S
STM32L1xx	Doublebuffered 8 endpoints	usbd_devfs	usbd_stm32l100_devfs.c
		usbd_devfs_asm	usbd_stm32l100_devfs_asm.S
STM32F102 STM32F103 STM32F302 STM32F303 STM32F373	Doublebuffered External DP pullup 8 endpoints	usbd_devfs	usbd_stm32f103_devfs.c
		usbd_devfs_asm	usbd_stm32f103_devfs_asm.S
STM32L4x5 STM32L4x6	Doublebuffered 6 endpoints BC1.2 VBUS detection	usbd_otgfs	usbd_stm32l476_otgfs.c
STM32F4x5 STM32F4x7 STM32F4x9	Doublebuffered 6 endpoints VBUS detection SOF output	usbd_otgfs	usbd_stm32l429_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

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

Using makefile

• to build library module

make module MODULE=path/module.a DEFINES="mcu spcified defines" CFLAGS="cpu cpecified 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

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