UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
507 of 1269
NXP Semiconductors
UM10503
Chapter 23: LPC43xx USB0 Host/Device/OTG controller
23.5.1 Requirements for connecting the USB0_VBUS/USB1_VBUS signal
The USB0_VBUS and USB1_VBUS pins are only 5 V tolerant when VDDIO is present.
Therefore, special precautions are necessary when the USB0 controller is implemented
as a USB-powered USB device or an OTG product.
For a USB OTG product, it is important to be able to detect the VBUS level and to charge
and discharge VBUS. This requires adding active devices that disconnect the link when
VDDIO is not present.
23.6 Register description
USB0_VBUS
I
VBUS pin (power on USB cable). This pin includes an internal pull-down resistor of
64 kOhm (typical) ± 16 kOhm. For maximum load C
L
= 6.5 uF and maximum
pull-down resistor R
pd
= 80 kOhm, the VBUS signal takes about 2 s to fall from
VBUS = 5 V to VBUS = 0.2 V when it is no longer driven.
Remark:
This input is only 5 V tolerant when VDDIO is present.
USB0_ID
I
Indicates to the transceiver whether connected as an A-device (USB0_ID LOW) or
B-device (USB0_ID HIGH). For OTG this pin has an internal pull-up resistor.
USB0_RREF
-
12.0 k
(accuracy 1%) on-board resistor to ground for current reference;
USB0_VDDA3V3_
DRIVER
-
Separate analog 3.3 V power supply for driver.
USB0_VDDA3V3
-
USB 3.3 V separate power supply voltage
USB0_VSSA_TERM
-
Dedicated analog ground for clean reference for termination resistors.
USB0_VSSA_REF
-
Dedicated clean analog ground for generation of reference currents and voltages.
Table 391. USB0 pin description
Pin function
Direction
Description
Table 392. Register access abbreviations
Abbreviation
Description
R/W
Read/Write
R/WC
Read/Write one to Clear
R/WO
Read/Write Once
RO
Read Only
WO
Write Only
R/WS
Read/Write one to Set
Table 393. Register overview: USB0 OTG controller (register base address 0x4000 6000)
Name
Access Address
offset
Description
Reset
value
Reset value
after USB0
boot
Reference
-
-
0x000 -
0x0FF
Reserved
-
-
Device/host capability registers
CAPLENGTH
RO
0x100
Capability register length
0x0100
0040
0x0100
0040
HCSPARAMS
RO
0x104
Host controller structural parameters 0x0001
0011
0x0001
0011