Overview of USBX

USBX has a remarkably small minimal footprint of 10.5 KB of FLASH and 5.1 KB RAM for USBX Device CDC/ACM support. USBX Host requires a minimum of 18 KB of FLASH and 25 KB of RAM for CDC/ACM support.

An additional 10 KB to 13 KB of instruction area memory is needed for TCP functionality. USBX RAM usage typically ranges from 2.6 KB to 3.6 KB plus the packet pool memory, which is defined by the application.

Like ThreadX, the size of USBX automatically scales based on the services actually used by the application. This virtually eliminates the need for complicated configuration and build parameters, making things easier for the developer.

USBX Device Stack has been rigorously tested with the USB IF standard testing tool USBCV to ensure full compliance with the USB specifications and interoperability with different host systems. In addition, USBX OTG stack has been verified and certified by the independent test lab Allion in Taiwan.

USBX supports major USB standards like OHCI and EHCI. In addition, USBX supports proprietary discrete USB host controllers from Atmel, Microchip, Philips, Renesas, ST, TI, and other vendors. USBX also supports multiple host controllers in the same application. USB Device controller support USBX supports popular USB device controllers from Analog Devices, Atmel, Microchip, NXP, Philips, Renesas, ST, TI, and other vendors.

USBX Host provides support for most popular classes, including ASIX, AUDIO, CDC/ACM, CDC/ECM, GSER, HID (keyboard, mouse, and remote control), HUB, PIMA (PTP/MTP), PRINTER, PROLIFIC, and STORAGE.

USBX Device provides support for most popular classes, including CDC/ACM, CDC/ECM, DFU, HID, PIMA (PTP/MTP) (w/MTP), RNDIS, and STORAGE. Support for custom classes is also available.

USBX supports the full Pictbridge implementation both on the host and the device. Pictbridge sits on top of USBX PIMA (PTP/MTP) class on both sides. The PictBridge standard allows the connection of a digital still camera or a smart phone directly to a printer without a PC, enabling direct printing to certain Pictbridge aware printers. When a camera or phone is connected to a printer, the printer is the USB host and the camera is the USB device. However, with Pictbridge, the camera will appear as being the host and commands are driven from the camera. The camera is the storage server, the printer the storage client. The camera is the print client and the printer is of course the print server. Pictbridge uses USB as a transport layer but relies on PTP (Picture Transfer Protocol) for the communication protocol.

USBX Host and Device support custom classes. An example custom class is provided in the USBX distribution. This simple data pump class is called DPUMP and can be used as a model for custom application classes. Advanced technology USBX Host and Device support custom classes. An example custom class is provided in the USBX distribution. USBX is advanced technology that includes:

The USBX Host API is an intuitive and consistent API, following a noun-verb naming convention. All APIs have leading ux_host_* to easily identify as USBX. Any blocking APIs have optional thread timeout.

The USBX Device API is an intuitive and consistent API following a noun-verb naming convention. All APIs have leading ux_device_* to easily identify as USBX. Blocking APIs have optional thread timeout. Please see USBX Host User Guide for more details.