Demonstration Kit Software; Design Firmware Upgrade; Usb Audio Device Class - ST STM32 User Manual

Demonstration kit software

11 Demonstration kit software
This section presents the main ready-to-use software techniques that are implemented on
the STM32 performance line USB demonstration kit.
11.1

Design firmware upgrade

This paragraph describes the implementation of a device firmware upgrade (DFU) capability
in the STM32F103xx microcontroller. It follows the DFU class specification defined by the
USB Implementers Forum for reprogramming an application through USB. The DFU
principle is particularly well suited for the USB applications that need to be reprogrammed in
the field: The same USB connector can be used for both the standard operating mode and
the reprogramming process.
This operation is made possible by the IAP capability featured by most of the
STMicroelectronics USB Flash microcontrollers, which allows a Flash MCU to be
reprogrammed by any communication channel.
The DFU process, like any other IAP process, is based on the execution of firmware located
in one small part of the Flash memory. This firmware manages the erase and program of the
others Flash memory areas, depending on the device features:
Main program/Code Flash, data Flash/EEPROM, or any other memory connected to the
microcontroller including serial I
The STM32 performance line USB demonstration kit features DFU capability used to
program the internal Flash memory.
Refer to the UM0412, Getting started with DfuSe USB device firmware upgrade
STMicroelectronics extension (available online from: www.st.com/mcu), for more details on
the driver installation and PC user interface.
11.2

USB Audio Device Class

An audio device, as defined by the Universal Serial Bus Class Definition for audio devices
specification, is a device or a function embedded in composite devices that are used to
manipulate audio, voice, and sound-related functionality. This includes both audio data
(analog and digital) and the functionality that is used to directly control the audio
environment, such as volume and tone control.
All audio devices are grouped, from the USB-FS-device point of view, in the audio interface
class. This class is divided into several subclasses. The Universal Serial Bus Class
Definition for audio devices specification details the three following subclasses:
●
AudioControl Interface subclass (AC): each audio function has a single
AudioControl interface. The AC interface is used to control the functional behavior of
a particular audio function. To achieve this functionality, this interface can use the
following endpoints:
– A control endpoint (endpoint 0) for manipulating unit and terminal settings and
retrieving the state of the audio function using class-specific requests.
– An interrupt endpoint for status returns. This endpoint is optional. The
AudioControl interface is the single entry point to access the internals of the audio
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C or SPI Flash memories).
Doc ID 15867 Rev 1
UM0722