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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
182 of 808
1.
How to read this chapter
This chapter describes the USB controller which is present on all LPC17xx devices. On
some LPC17xx family devices, the USB controller can also be configured for Host or OTG
operation instead of device.
2.
Basic configuration
The USB controller is configured using the following registers:
1. Power: In the PCONP register (
), set bit PCUSB.
Remark:
On reset, the USB block is disabled (PCUSB = 0).
2. Clock: The USB block can be used with a dedicated PLL to obtain the USB clock or
).
3. Pins: Select USB pins and their modes in PINSEL0 to PINSEL5 and PINMODE0 to
).
4. Wake-up: Activity on the USB bus port can wake up the microcontroller from
Power-down mode, see
.
5. Interrupts: Interrupts are enabled in the NVIC using the appropriate Interrupt Set
Enable register.
6. Initialization: see
.
3.
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 LPC17xx enables full-speed (12 Mb/s) data exchange
with a USB host controller.
UM10360
Chapter 11: LPC17xx USB device controller
Rev. 00.06 — 5 June 2009
User manual