USBD_Midi_Desc

Files: usbd_midi_desc.c
Directory: DAD_FORGE/Drivers/_MIDI Description: USB descriptor management for Full Speed MIDI device

📋 Class Description

USB MIDI descriptors implementation module (USB MIDI Device Class). This module provides all necessary functions to generate and return USB descriptors required by the USB Host Controller system, including device descriptor, string descriptors (manufacturer, product, serial, configuration, interface), and language ID. It is specifically designed for Full Speed (FS) operation with a MIDI device named “OSCAR MIDI”.

🎯 Enumerations and Associated Structures

The class uses the external USBD_DescriptorsTypeDef structure defined in the standard USB framework.

📚 Mandatory Functions

USBD_Midi_FS_DeviceDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_DeviceDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the USB device descriptor containing basic MIDI device information (vendor ID, product ID, version number, maximum packet size)
Parameter(s)
`speed`	USB speed type (Full Speed or High Speed). Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the device descriptor (`USBD_Midi_FS_DeviceDesc`).

USBD_Midi_FS_LangIDStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_LangIDStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the Language ID string descriptor indicating the USB device’s language (French - code 1036).
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the Language ID descriptor (`USBD_Midi_LangIDDesc`).

USBD_Midi_FS_ManufacturerStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_ManufacturerStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the string descriptor containing the manufacturer name (“STMicroelectronics”). The string is converted to USB Unicode format.
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the manufacturer string descriptor (`USBD_Midi_StrDesc`).

USBD_Midi_FS_ProductStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_ProductStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the string descriptor containing the product name (“OSCAR MIDI”). The string is converted to USB Unicode format.
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the product string descriptor (`USBD_Midi_StrDesc`).

USBD_Midi_FS_SerialStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_SerialStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the string descriptor containing a unique serial number generated from the microcontroller’s hardware identifiers (DEVICE_ID1, DEVICE_ID2, DEVICE_ID3).
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the serial number (`USBD_Midi_StringSerial`).

USBD_Midi_FS_ConfigStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_ConfigStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the string descriptor containing the configuration description (“MIDI Config”). The string is converted to USB Unicode format.
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the configuration string descriptor (`USBD_Midi_StrDesc`).

USBD_Midi_FS_InterfaceStrDescriptor

Element	Details
Method	`uint8_t * USBD_Midi_FS_InterfaceStrDescriptor(USBD_SpeedTypeDef speed, uint16_t *length)`
Description	Returns the string descriptor containing the interface description (“MIDI Interface”). The string is converted to USB Unicode format.
Parameter(s)
`speed`	USB speed type. Parameter ignored for this Full Speed device.
`length`	Pointer to a variable that will receive the length of the returned descriptor in bytes.
Return	Pointer to the buffer containing the interface string descriptor (`USBD_Midi_StrDesc`).

📚 Utility Functions

Get_SerialNum

Element	Details
Method	`static void Get_SerialNum(void)`
Description	Generates a unique serial number by combining the microcontroller’s hardware identifiers (DEVICE_ID1, DEVICE_ID2, DEVICE_ID3) and converts the result to Unicode format for storage in the serial string buffer.
Parameter(s)	No parameters. Static method with no arguments.
Return	No return value (void). Directly modifies the `USBD_Midi_StringSerial` buffer.

IntToUnicode

Element	Details
Method	`static void IntToUnicode(uint32_t value, uint8_t * pbuf, uint8_t len)`
Description	Converts a 32-bit integer value to a hexadecimal Unicode character string (high-speed USB ASCII format). Each nibble is converted to a ‘0’-‘9’ or ‘A’-‘F’ character.
Parameter(s)
`value`	32-bit integer value to convert.
`pbuf`	Pointer to the destination buffer for the Unicode string (must be aligned).
`len`	Maximum conversion length in bytes (number of nibbles × 2).
Return	No return value (void).

📦 Data

Member	Type	Description
`USBD_Midi_FS_DeviceDesc`	`uint8_t[USB_LEN_DEV_DESC]`	Buffer containing the USB device descriptor (type, version, vendor/product ID, maximum packet size, etc.). Memory aligned.
`USBD_Midi_LangIDDesc`	`uint8_t[USB_LEN_LANGID_STR_DESC]`	Buffer containing the Language ID descriptor (code 1036 = French). Memory aligned.
`USBD_Midi_StrDesc`	`uint8_t[USBD_MAX_STR_DESC_SIZ]`	Generic buffer for Unicode string descriptors (manufacturer, product, configuration, interface). Reused by multiple functions.
`USBD_Midi_StringSerial`	`uint8_t[USB_SIZ_STRING_SERIAL]`	Buffer containing the device’s unique serial number, generated from hardware identifiers. Memory aligned.
`FS_Midi_Desc`	`USBD_DescriptorsTypeDef`	Structure aggregating callbacks for all USB MIDI descriptors (pointer to each descriptor function).