UM10211 - Standard ICs

UM10211
Chapter 13: USB device controller
Rev. 01 — 27 March 2007
User manual
1. Introduction
The Universal Serial Bus (USB) is a four-wire bus that supports communication between a
host and one or more (up to 127) peripherals. The host controller allocates the USB
bandwidth to attached devices through a token-based protocol. The bus supports hot
plugging and dynamic configuration of the devices. All transactions are initiated by the
host controller.
The host schedules transactions in 1 ms frames. Each frame contains a Start-Of-Frame
(SOF) marker and transactions that transfer data to or from device endpoints. Each device
can have a maximum of 16 logical or 32 physical endpoints. There are four types of
transfers defined for the endpoints. Control transfers are used to configure the device.
Interrupt transfers are used for periodic data transfer. Bulk transfers are used when the
rate of transfer is not critical. Isochronous transfers have guaranteed delivery time but no
error correction.
For more information on the Universal Serial Bus, see the USB Implementers Forum
website.
The USB device controller on the LPC23xx enables full-speed (12 Mb/s) data exchange
with a USB host controller.
Table 233. USB related acronyms, abbreviations, and definitions used in this chapter
Acronym/abbreviation
AHB
ATLE
ATX
DD
DDP
DMA
EOP
EP
EP_RAM
FS
LED
LS
MPS
NAK
PLL
RAM
SOF
SIE
Description
Advanced High-performance bus
Auto Transfer Length Extraction
Analog Transceiver
DMA Descriptor
DMA Description Pointer
Direct Memory Access
End-Of-Packet
Endpoint
Endpoint RAM
Full Speed
Light Emitting Diode
Low Speed
Maximum Packet Size
Negative Acknowledge
Phase Locked Loop
Random Access Memory
Start-Of-Frame
Serial Interface Engine
UM10211_1
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