Glossary

BSP

Board Support Package. A collection of board-specific code that provides hardware abstraction for a particular development board, including pin mappings, clock settings, linker scripts, and hardware initialization routines. Located in hw/bsp/FAMILY/boards/BOARD_NAME.

Bulk Transfer

USB transfer type used for large amounts of data that doesn’t require guaranteed timing. Used by mass storage devices and CDC class.

CDC

Communications Device Class. USB class for devices that communicate serial data, creating virtual serial ports.

Control Transfer

USB transfer type used for device configuration and control. All USB devices must support control transfers on endpoint 0.

DCD

Device Controller Driver. The hardware abstraction layer for USB device controllers in TinyUSB. See also HCD.

Descriptor

Data structures that describe USB device capabilities, configuration, and interfaces to the host.

Device Class

USB specification defining how devices of a particular type (e.g., storage, audio, HID) communicate with hosts.

DFU

Device Firmware Update. USB class that allows firmware updates over USB.

Endpoint

Communication channel between host and device. Each endpoint has a direction (IN/OUT) and transfer type.

Enumeration

Process where USB host discovers and configures a newly connected device.

HCD

Host Controller Driver. The hardware abstraction layer for USB host controllers in TinyUSB. See also DCD.

HID

Human Interface Device. USB class for input devices like keyboards, mice, and game controllers.

High Speed

USB 2.0 speed mode operating at 480 Mbps.

Full Speed

USB speed mode operating at 12 Mbps, supported by USB 1.1 and 2.0.

Low Speed

USB speed mode operating at 1.5 Mbps, typically used by simple input devices.

Interrupt Transfer

USB transfer type for small, time-sensitive data with guaranteed maximum latency.

Isochronous Transfer

USB transfer type for time-critical data like audio/video with guaranteed bandwidth but no error correction.

MSC

Mass Storage Class. USB class for storage devices like USB drives.

OSAL

Operating System Abstraction Layer. TinyUSB component that abstracts RTOS differences.

OTG

On-The-Go. USB specification allowing devices to act as both host and device.

Pipe

Host-side communication channel to a device endpoint.

Root Hub

The USB hub built into the host controller, where devices connect directly.

Stall

USB protocol mechanism where an endpoint responds with a STALL handshake to indicate an error condition or unsupported request. Used for error handling, not flow control.

Super Speed

USB 3.0 speed mode operating at 5 Gbps. Not supported by TinyUSB.

tud

TinyUSB Device. Function prefix for all device stack APIs (e.g., tud_task(), tud_cdc_write()).

tuh

TinyUSB Host. Function prefix for all host stack APIs (e.g., tuh_task(), tuh_cdc_receive()).

UAC

USB Audio Class. USB class for audio devices.

UVC

USB Video Class. USB class for video devices like cameras.

VID

Vendor Identifier. 16-bit number assigned by USB-IF to identify device manufacturers.

PID

Product Identifier. 16-bit number assigned by vendor to identify specific products.

USB-IF

USB Implementers Forum. Organization that maintains USB specifications and assigns VIDs.