Str7/Str9 Usb Firmware Library; Usb Application Hierarchy - ST STR9 User Manual

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STR7/STR9 USB firmware library

This section describes the firmware interface (called USB Library) used to manage the
STR7/9 USB 2.0 full-speed macrocell.
The main purpose of this firmware library is to provide resources to ease the development of
applications using the USB macrocell in all STR7/9 microcontrollers (STR71x, STR75x and
the STR91x families).
1.1

USB application hierarchy

Figure 1
application and the USB library.
Figure 1.
The USB library is divided into two layers:
●
USB Library Core layer: This layer manages the direct communication with the USB
IP hardware and the USB standard protocol. The USB Library Core is compliant with
the USB 2.0 specification and doesn't have dependences with any Standard Software
Library of STR7/9 microcontrollers.
●
Application Interface layer: This layer presents to the user a complete interface
between the library core and the final application.
Note: The application interface layer and the final application can communicate with the Standard
Software Library to manage the hardware needs of the application.
shows the interaction between the different components of a typical USB
USB application hierarchy
USB Application
usb_pwr
usb_istr usb_prop
usb_core
usb_init
usb_regs
usb_int
USB IP
usb_desc
Application Interface
usb_endp
USB Library
Core
usb_mem
Hardware (STR microcontroller + Board)
STR7/STR9 USB firmware library
Standard
Library
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