
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
14 of 487
NXP Semiconductors
UM10800
Chapter 3: LPC82x Boot ROM
3.6.3 Boot process flowchart
(1) The boot-code is implementing auto-baud in software.
(2) This step is included for backward compatibility and the response is ignored by the bootloader.
Fig 4.
Boot process flowchart
RESET
INITIALIZE
RECEIVE CRYSTAL FREQUENCY
(2)
RUN UART ISP COMMAND HANDLER
RUN AUTO-BAUD
(1)
CRP1/2/3
ENABLED?
WATCHDOG
FLAG SET?
CRP3/NO_ISP
ENABLED?
ENTER ISP
MODE?
(ISP ENTRY PIN
= LOW)
USER CODE
VALID?
USER CODE
VALID?
AUTO-BAUD
SUCCESSFUL?
EXECUTE INTERNAL
USER CODE
ENABLE DEBUG
yes
yes
yes
yes
yes
yes
yes
no
no
no
no
no
no
no
no
A
A
boot from
UART