UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
37 of 1269
NXP Semiconductors
UM10503
Chapter 5: LPC43xx Boot ROM
Fig 11. Boot process
4 of
LPC
18
xx RESET
disable
IRQ &
MPU
CPU clock
= IRC
12
MHz
check BOOT
_
SRC
AES
capable and
key
>
0
?
load AES
key
yes
UART
0
boot
check pins
P
2
_
9
,
P
2
_
8
,
P
1
_
2
,
P
1
_
1
= 0
=
0
EMC 8
b
boot
EMC 32
b
boot
EMC 16
b
boot
= 1
>
10
enable
JTAG
no
valid
Header
?
yes
yes
no
no
AES capable
and CMAC
active
?
yes
copy image to
SRAM and
calculate
CMAC tag
valid tag
?
decrypt image
in SRAM
yes
set Shadow Pointer
= 0
x
1000 0000
development
mode
?
yes
no
copy image to
SRAM
Reset
no
=
1
..
4
,
7
CPU clock
=
96
MHz
read Header
read
Header
=
2
..
5
,
8
>
9
set Shadow Pointer
= 0
x
1000 0000
set Shadow Pointer
= boot address
no
SPI
boot
UART
3
boot
=
6
..
7
,
9
USB
0
boot
USB
1
boot
BOOT
_
SRC
=
6
or pins
=
5
BOOT
_
SRC
=
7
or pins
=
6
BOOT
_
SRC
=
9
or pins
=
8
BOOT _
SRC=
8
or pins
=
7
BOOT
_SRC
=
2
or pins
=
1
BOOT
_
SRC
=
3
or pins
=
2
BOOT
_
SRC
=
4
or pins
=
3
BOOT
_
SRC
=
5
or pins
=
4
BOOT
_
SRC
=
1
or pins
=
0
valid
Header
?
yes
no
60
s timeout
toggle pin
P
1
_
1
Header
present?
SPIFI boot