Datasheet

Product data sheet Rev. 1.2 — 26 May 2014 27 of 96

NXP Semiconductors

LPC11U6x

32-bit ARM Cortex-M0+ microcontroller

8.14 USB interface

The Universal Serial Bus (USB) is a 4-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 USB interface consists of a full-speed device controller with on-chip PHY (PHYsical

layer) for device functions.

Remark: Configure the part in default power mode with the power profiles before using

the USB (see Section 8.25.7.1 “

Power profiles”). Do not use the USB when the part runs

in performance, efficiency, or low-power mode.

8.14.1 Full-speed USB device controller

The device controller enables 12 Mbit/s data exchange with a USB Host controller. It

consists of a register interface, serial interface engine, and endpoint buffer memory. The

serial interface engine decodes the USB data stream and writes data to the appropriate

endpoint buffer. The status of a completed USB transfer or error condition is indicated via

status registers. An interrupt is also generated if enabled.

8.14.1.1 Features

• Dedicated USB PLL available.

• Fully compliant with USB 2.0 specification (full speed).

• Supports 10 physical (5 logical) endpoints including one control endpoint.

• Single and double buffering supported.

• Each non-control endpoint supports bulk, interrupt, or isochronous endpoint types.

• Supports wake-up from Deep-sleep mode and Power-down mode on USB activity

and remote wake-up.

• Supports SoftConnect functionality through internal pull-up resistor.

• Internal 33  series termination resistors on USB_DP and USB_DM lines eliminate

the need for external series resistors.

• Supports Link Power Management (LPM).

• Supports XTAL-less low-speed mode using the 1% accurate IRC as the clock source

for the USB PLL. For board connection changes in low-speed mode, see Section

14.3.1 “USB Low-speed operation”.

8.15 USART0

Remark: The LPC11U6x contains two distinctive types of UART interfaces: USART0 is

software-compatible with the USART interface on the LPC11U1x/LPC11U2x/LPC11U3x

parts. USART1 to USART4 use a different register interface.

The USART0 includes full modem control, support for synchronous mode, and a smart

card interface. The RS-485/9-bit mode allows both software address detection and

automatic address detection using 9-bit mode.

The USART0 uses a fractional baud rate generator. Standard baud rates such as

115200 Bd can be achieved with any crystal frequency above 2 MHz.