CPPI
DMA
Engine
FIFO
Packet
Encode/
Decode
USB
2.0
PHY
USB
REFCLK
(Optional)
Registers, Interrupts, Endpoint Control,
and Packet Scheduling
Internal
Bus
Introduction
1607
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Serial Bus 2.0 (USB) Controller
34.1 Introduction
The controller complies with the USB 2.0 standard high-speed and full-speed functions and low-speed,
full-speed, and high-speed limited host mode operations. It also includes support for the Session Request
and Host Negotiation Protocols used in point-to-point communications, details of which are given in the
USB On-The-Go supplement to the USB 2.0 specification. In addition, the four test modes for high-speed
operation described in the USB 2.0 specification are supported. It also allows options that allow the USB
controller to be forced into full-speed mode, high-speed mode, or host mode that may be used for debug
purposes.
34.1.1 Purpose of the Peripheral
The USB controller provides a low-cost connectivity solution for consumer portable devices by providing a
mechanism for data transfer between USB devices up to 480 Mbps. Its support for a dual-role feature
allows for additional versatility supporting operation capability as a host or peripheral.
34.1.2 Features
The USB has the following features:
•
Operating as a host, it complies with the USB 2.0 standard for high-speed (480 Mbps), full-speed
(12 Mbps), and low-speed (1.5 Mbps) operations with a peripheral
•
Operating as a peripheral, it complies with the USB 2.0 standard for high-speed (480 Mbps) and full-
speed (12 Mbps) operation with a host.
•
Supports USB extensions for Session Request (SRP) and Host Negotiation (HNP) – OTG
•
Supports 4 simultaneous RX and TX endpoints, in addition to control endpoint, more devices can be
supported by dynamically switching endpoints states
•
Each endpoint (other than endpoint 0) can support all transfer types (control, bulk, interrupt, and
isochronous)
•
Includes a 4K endpoint FIFO RAM, and supports programmable FIFO sizes
•
External 5V power supply for VBUS, when operating as host, enabled directly by the USB controller
through a dedicated signal
•
Includes a DMA controller that supports 4 TX and 4 RX DMA channels
•
Includes four types of Communications Port Programming Interface (CPPI) 4.1 DMA compliant transfer
modes, Transparent, Generic RNDIS, RNDIS, and Linux CDC mode of DMA for accelerating RNDIS
type protocols using short packet termination over USB.
•
DMA supports single data transfer size up to 4Mbytes
34.1.3 Functional Block Diagram
The USB functional block diagram is shown in
Figure 34-1. Functional Block Diagram