NXP Semiconductors LPC24XX UM10237 - Manual (Page 334)

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User manual Rev. 04 — 26 August 2009 334 of 792
NXP Semiconductors
UM10237
Chapter 13: LPC24XX USB device controller
Once data has been received or sent, the endpoint buffer can be read or written. How this
is accomplished depends on the endpoint’s type and operating mode. The two operating
modes for each endpoint are Slave (CPU-controlled) mode, and DMA mode.
In Slave mode, the CPU transfers data between RAM and the endpoint buffer using the
Register Interface. See
Section 13–13 “Slave mode operation” for a detailed description of
this mode.
In DMA mode, the DMA transfers data between RAM and the endpoint buffer. See
Section 13–14 “DMA operation” for a detailed description of this mode.
7. Pin description
The device controller can access two USB ports indicated by suffixes 1 and 2 in the USB
pin names and referred to as USB port 1 (U1) and USB port 2 (U2) in the following text.
7.1 USB device usage note
The USB device interface can be routed to either USB port1 (using USB_CONNECT1,
USB_UP_LED1, USB_D+1, USB_D
−1) or USB port2 (using USB_CONNECT2,
USB_UP_LED2, USB_D+2, USB_D
−2) to allow for more versatile pin multiplexing (see
Section 13–9.1.1 “USB Port Select register (USBPortSel - 0xFFE0 C110)” ).
To use both ports for USB transfer, port1 has to be configured as host and port2 has to be
configured as device. See
Section 15–6.3 “Connecting USB as one port host and one port
device” on page 399 for details.
The USB device/host/OTG controller is disabled after RESET and must be enabled by
writing a 1 to the PCUSB bit in the PCONP register, see
Table 4–63 .
8. Clocking and power management
This section describes the clocking and power management features of the USB Device
Controller.
Table 291. USB device pin description
Name Direction Description
V
BUS
I V
BUS
status input. When this function is not enabled
via its corresponding PINSEL register, it is driven
HIGH internally.
USB_CONNECT1,
USB_CONNECT2 O SoftConnect control signal.
USB_UP_LED1,
USB_UP_LED2 O GoodLink LED control signal.
USB_D+1, USB_D+2 I/O Positive differential data.
USB_D
−1, USB_D−2
I/O Negative differential data.