rt-thread/components/drivers/usb/cherryusb/README.md

CherryUSB

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中文 | English

CherryUSB is a tiny and beautiful, high performance and portable USB host and device stack for embedded system with USB IP.

Why choose

Easy to study USB

In order to make it easier for users to learn USB basics, enumeration, driver loading and IP drivers, the code has been written with the following advantages:

• Lean code, simple logic, no complex C syntax
• Tree-based programming with cascading code
• Class-drivers and porting-drivers are templating and simplification
• Clear API classification (slave: initialisation, registration api, command callback api, data sending and receiving api; host: initialisation, lookup api, data sending and receiving api)

Easy to use USB

In order to facilitate the use of the USB interface and to take into account the fact that users have learned about uart and dma, the following advantages have been designed for the data sending and receiving class of interface:

• Equivalent to using uart tx dma/uart rx dma
• There is no limit to the length of send and receive, the user does not need to care about the USB packetization process (the porting driver does it)

Easy to bring out USB performance

Taking into account USB performance issues and trying to achieve the theoretical bandwidth of the USB hardware, the design of the data transceiver class interface has the following advantages:

• Porting drivers directly to registers, no abstraction layer encapsulation
• Memory zero copy
• If IP has DMA then uses DMA mode (DMA with hardware packetization)
• Unlimited length make it easier to interface with hardware DMA and take advantage of DMA
• Packetization is handled in interrupt

Directory Structure

Directory	Description
class	usb class driver
common	usb spec macros and utils
core	usb core implementation
demo	usb device and host demo
osal	os wrapper
platform	class support for other os
docs	doc for guiding
port	usb dcd and hcd porting
tools	tool url

Device Stack Overview

CherryUSB Device Stack provides a unified framework of functions for standard device requests, CLASS requests, VENDOR requests and custom special requests. The object-oriented and chained approach allows the user to quickly get started with composite devices without having to worry about the underlying logic. At the same time, a standard dcd porting interface has been standardised for adapting different USB IPs to achieve ip-oriented programming.

CherryUSB Device Stack has the following functions：

• Support USB2.0 full and high speed, USB3.0 super speed
• Support endpoint irq callback register by users, let users do whatever they wants in endpoint irq callback.
• Support Composite Device
• Support Communication Device Class (CDC_ACM, CDC_ECM)
• Support Human Interface Device (HID)
• Support Mass Storage Class (MSC)
• Support USB VIDEO CLASS (UVC1.0、UVC1.5)
• Support USB AUDIO CLASS (UAC1.0、UAC2.0)
• Support Device Firmware Upgrade CLASS (DFU)
• Support USB MIDI CLASS (MIDI)
• Support Remote NDIS (RNDIS)
• Support WINUSB1.0、WINUSB2.0、WEBUSB、BOS
• Support Vendor class
• Support UF2
• Support Android Debug Bridge (Only support shell)
• Support multi device with the same USB IP

CherryUSB Device Stack resource usage (GCC 10.2 with -O2):

file	FLASH (Byte)	No Cache RAM (Byte)	RAM (Byte)	Heap (Byte)
usbd_core.c	~4400	512(default) + 320	0	0
usbd_cdc_acm.c	~400	0	0	0
usbd_msc.c	~3800	128 + 512(default)	16	0
usbd_hid.c	~360	0	0	0
usbd_audio.c	~1500	0	0	0
usbd_video.c	~2600	0	84	0
usbd_rndis.c	~2100	2 * 1580(default)+156+8	76	0

Host Stack Overview

The CherryUSB Host Stack has a standard enumeration implementation for devices mounted on roothubs and external hubs, and a standard interface for different Classes to indicate what the Class driver needs to do after enumeration and after disconnection. A standard hcd porting interface has also been standardised for adapting different USB IPs for IP-oriented programming. Finally, the host stack is managed using os, and provides osal to make a adaptation for different os.

CherryUSB Host Stack has the following functions：

• Support low speed, full speed, high speed and super speed devices
• Automatic loading of supported Class drivers
• Support blocking transfers and asynchronous transfers
• Support Composite Device
• Multi-level HUB support, expandable up to 7 levels(Testing hub with 10 ports works well,only support dwc2/ehci/xhci/rp2040)
• Support Communication Device Class (CDC_ACM, CDC_ECM)
• Support Human Interface Device (HID)
• Support Mass Storage Class (MSC)
• Support USB Video CLASS (UVC1.0、UVC1.5)
• Support USB Audio CLASS (UAC1.0)
• Support Remote NDIS (RNDIS)
• Support USB Bluetooth class (support nimble and zephyr bluetooth stack, support CLASS:0xE0 or vendor class like cdc acm)
• Support Vendor class (serial, net, wifi)
• Support USB modeswitch
• Support Android Open Accessory
• Support multi host with the same USB IP

The CherryUSB Host stack also provides the lsusb function, which allows you to view information about all mounted devices, including those on external hubs, with the help of a shell plugin.

CherryUSB Host Stack resource usage (GCC 10.2 with -O2):

file	FLASH (Byte)	No Cache RAM (Byte)	RAM (Byte)	Heap (Byte)
usbh_core.c	~9000	512 + 8 * (1+x) *n	28	raw_config_desc
usbh_hub.c	~6000	32 + 4 * (1+x)	12 + sizeof(struct usbh_hub) * (1+x)	0
usbh_cdc_acm.c	~900	7	4 + sizeof(struct usbh_cdc_acm) * x	0
usbh_msc.c	~2700	64	4 + sizeof(struct usbh_msc) * x	0
usbh_hid.c	~1400	256	4 + sizeof(struct usbh_hid) * x	0
usbh_video.c	~3800	128	4 + sizeof(struct usbh_video) * x	0
usbh_audio.c	~4100	128	4 + sizeof(struct usbh_audio) * x	0
usbh_rndis.c	~4200	512 + 2 * 2048(default)	sizeof(struct usbh_rndis) * 1	0
usbh_cdc_ecm.c	~2200	2 * 1514 + 16	sizeof(struct usbh_cdc_ecm) * 1	0
usbh_cdc_ncm.c	~3300	2 * 2048(default) + 16 + 32	sizeof(struct usbh_cdc_ncm) * 1	0
usbh_bluetooth.c	~1000	2 * 2048(default)	sizeof(struct usbh_bluetooth) * 1	0

Among them, sizeof(struct usbh_hub) and sizeof(struct usbh_hubport) are affected by the following macros：

#define CONFIG_USBHOST_MAX_EXTHUBS          1
#define CONFIG_USBHOST_MAX_EHPORTS          4
#define CONFIG_USBHOST_MAX_INTERFACES       8
#define CONFIG_USBHOST_MAX_INTF_ALTSETTINGS 8
#define CONFIG_USBHOST_MAX_ENDPOINTS        4

x is affected by the following macros：

#define CONFIG_USBHOST_MAX_CDC_ACM_CLASS 4
#define CONFIG_USBHOST_MAX_HID_CLASS     4
#define CONFIG_USBHOST_MAX_MSC_CLASS     2
#define CONFIG_USBHOST_MAX_AUDIO_CLASS   1
#define CONFIG_USBHOST_MAX_VIDEO_CLASS   1

USB IP Support

Only standard and commercial USB IP are listed.

IP	device	host	Support status
OHCI(intel)	none	OHCI	√
EHCI(intel)	none	EHCI	√
XHCI(intel)	none	XHCI	√
UHCI(intel)	none	UHCI	×
DWC2(synopsys)	DWC2	DWC2	√
MUSB(mentor)	MUSB	MUSB	√
FOTG210(faraday)	FOTG210	EHCI	√
CHIPIDEA(synopsys)	CHIPIDEA	EHCI	√
CDNS2(cadence)	CDNS2	CDNS2	√
CDNS3(cadence)	CDNS3	XHCI	×
DWC3(synopsys)	DWC3	XHCI	×

Documentation Tutorial

Quickly start, USB basic concepts, API manual, Class basic concepts and examples, see CherryUSB Documentation Tutorial

Video Tutorial

USB basic concepts and how the CherryUSB Device stack is implemented, see CherryUSB Device Stack Tutorial.

Graphical Config Tool

chryusb_configurator is written in electron + vite2 + ts framework，currently used to automate the generation of descriptor arrays, with additional functionality to be added later.

Demo Repo

Manufacturer	CHIP or Series	USB IP	Repo Url	Support version	Support status
Bouffalolab	BL702/BL616/BL808	bouffalolab/ehci	bouffalo_sdk	<= latest	Long-term
ST	STM32F1x	fsdev	stm32_repo	<= latest	Long-term
ST	STM32F4/STM32H7	dwc2	stm32_repo	<= latest	Long-term
HPMicro	HPM6000/HPM5000	hpm/ehci	hpm_sdk	<= latest	Long-term
Essemi	ES32F36xx	musb	es32f369_repo	<= latest	Long-term
Phytium	e2000	pusb2/xhci	phytium_repo	>=1.4.0	Long-term
Artinchip	d12x/d13x/d21x	aic/ehci/ohci	luban-lite	<= latest	Long-term
Espressif	esp32s2/esp32s3/esp32p4	dwc2	esp32_repo	<= latest	Long-term
NXP	mcx	kinetis/chipidea/ehci	nxp_mcx_repo	<= latest	Long-term
Kendryte	k230	dwc2	k230_repo	v1.2.0	Long-term
Raspberry pi	rp2040/rp2350	rp2040	pico-examples	<= latest	Long-term
AllwinnerTech	F1C100S/F1C200S	musb	cherryusb_rtt_f1c100s	<= latest	the same with musb
Bekencorp	bk7256/bk7258	musb	bk_idk	v0.7.0	the same with musb
Sophgo	cv18xx	dwc2	cvi_alios_open	v0.7.0	TBD
WCH	CH32V307/ch58x	ch32_usbfs/ch32_usbhs/ch58x	wch_repo	<= v0.10.2	TBD

Package Support

CherryUSB package is available as follows:

• RT-Thread
• YOC
• ESP-Registry

Commercial Support

Refer to https://cherryusb.readthedocs.io/zh-cn/latest/support/index.html.

Contact

CherryUSB discord: https://discord.com/invite/wFfvrSAey8.

Company Support

Thanks to the following companies for their support (in no particular order).