UM0290 datasheet(14/76 Pages) STMICROELECTRONICS

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STR7/STR9 USB firmware library

UM0290

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1.2.3

usb_int (.c , .h)

The usb_int module handles the correct transfer interrupt service routines; it offers the link

between the USB protocol events and the library core.

The STR7 USB IP provides two correct transfer routines:

●

Low priority interrupt: managed by the function CTR_LP() and used for the control,

interrupt and bulk (in simple buffer mode).

●

High priority interrupt: managed by the function CTR_HP() and used for faster transfer

mode like Isochronous and bulk (in double buffer mode).

1.2.4

usb_core (.c , .h)

The usb_core module is the kernel of the library. It implements all the functions described in

chapter 9 of the USB 2.0 specification.

The available subroutines cover handling of USB standard requests related to the control

endpoint (EP0), offering the necessary code to accomplish the sequence of enumeration

phase.

A state machine is implemented in order to process the different stages of the setup

transactions.

The USB core module implements also a dynamic interface between the standard request

and the user implementation using the structure User_Standard_Requests.

The USB core dispatches the class specific requests and some bus events to user program

whenever it is necessary. User handling procedures are given in the Device_Property

structure.

The different data and functions structures used by the kernel are described in the following

paragraphs.

Device table structure: The core keeps device level information in the structure

Device_Table. Device_Table with the type: DEVICE.

typedef struct _DEVICE {

u8 Total_Endpoint;

u8 Total_Configuration;

} DEVICE;

Device information structure: The USB core keeps the setup packet from the host for

the implemented USB device in the Device_Info structure. This structure has the type:

DEVICE_INFO.

typedef struct _DEVICE_INFO {

u8 USBbmRequestType;

u8 USBbRequest;

u16_u8 USBwValues;

u16_u8 USBwIndexs;

u16_u8 USBwLengths;

u8 ControlState;

u8 Current_Feature;

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