UM10850
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 2.4 — 13 September 2016
85 of 464
6.1 Features
•
64 KB on-chip boot ROM
•
Contains the boot loader with In-System Programming (ISP) facility and the following
APIs:
–
In-Application Programming (IAP) of flash memory
–
Power profiles for optimizing power consumption and system performance and for
controlling low power modes
6.2 Pin description
The parts support ISP via USART0. The ISP mode is determined by the state of the
P0_31 pin at boot time:
6.3 General description
The boot loader controls initial operation after reset and also provides the means to
program the flash memory. This could be initial programming of a blank device, erasure
and re-programming of a previously programmed device, or programming of the flash
memory by the application program in a running system.
The boot loader code is executed every time the part is powered on or reset (see
). The loader can execute the ISP command handler or the user application code.
The boot loader version can be read by ISP/IAP calls (see
Assuming that power supply pins are at their nominal levels when the rising edge on
RESET pin is generated, it may take up to 3 ms before the boot pins are sampled and the
decision whether to continue with user code or ISP handler is made. If the boot pins are
sampled LOW and the watchdog overflow flag is set, the external hardware request to
start the ISP command handler is ignored. If there is no request for the ISP command
handler execution, a search is made for a valid user program. If a valid user program is
found then the execution control is transferred to it. If a valid user program is not found,
the auto-baud routine is invoked.
See
Chapter 31 “LPC5410x Flash API”
for ISP and IAP commands.
UM10850
Chapter 6: LPC5410x Boot process
Rev. 2.4 — 13 September 2016
User manual
Table 105. ISP modes
Boot mode
P0_31
Description
No ISP
HIGH
ISP bypassed. Part attempts to boot from flash.
USART0
LOW
Part enters ISP via USART0.