UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
43 of 1269
NXP Semiconductors
UM10503
Chapter 5: LPC43xx Boot ROM
If no header is present, it is assumed that the image is located on address 0x8000 0000
and is executed from there.
5.3.5.5 USB boot mode
For booting from USB, two USB interfaces are available. USB0 supports high-speed and
full-speed while USB1 supports only full-speed. The USB clock is respectively set to
480 MHz or 60 MHz. USB1 requires VBUS pin to be set correctly. Initially, the USB0 PHY
is disabled to save some power. After it is enabled, enumeration can start. The DFU class
is used to download a boot image. After receiving a boot image from a host, the image is
validated based on a set of rules mentioned earlier. If valid, the image is processed
accordingly to address 0x1000 0000 and executed from there.
USB product and vendor ID are defined by the OTP (see
and
).
Fig 16. SPIFI boot process
Setup Pin
Configuration
P3_3..P3_8
Detect device
device
error?
activate
Vendor_ID
specific driver
yes
see main boot flow
Setup clock
SPIFI_SCK=
32MHz
if SQI device
supported
then 4-bit I/O
will be used
no
Reset
SPIFI_SCK=
18MHz
known
device?
no
yes