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UM10503
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2015. All rights reserved.
User manual
Rev. 2.1 — 10 December 2015
53 of 1441
5.1 How to read this chapter
This chapter applies to all parts. AES support is available on LPC43Sxx parts only. See
Chapter 7 “LPC43Sxx Boot ROM for secure parts”
Flash-based parts boot from on-chip flash by default (see
), but other boot
modes described in this chapter are also supported. The UART boot mode is only
supported for flashless parts. The secure boot from USART3 is not supported for
LPC43Sxx parts.
5.1.1 Determine the boot code version
For parts with on-chip flash, the boot code version can be determined using ISP or IAP
calls. See
Table 47 “ISP Read Boot Code version number command”
and
Read Boot Code version number command”
.
For flashless parts, use ISP to read the boot code version number (see
) or read
memory location 0x1040 7FFC which encodes the boot code version as follows:
Value 0x000B 000n at location 0x1040 7FFC reads as boot code version 11.n.
5.2 Features
The boot ROM memory includes the following features:
•
ROM memory size is 64 kB.
•
Supports booting from UART interfaces, external static memory such as NOR flash,
SPI flash, quad SPI flash, high-speed USB (USB0), and USB1.
•
Includes API for OTP programming.
•
Includes USB drivers.
•
ISP mode for loading data to on-chip SRAM and execute code from this location.
5.3 Functional description
The internal ROM memory is used to store the boot code. After a reset, the ARM
processor will start its code execution from this memory.
The ARM core is configured to start executing code, upon reset, with the program counter
being set to the value 0x0000 0000. The LPC43xx contains a shadow pointer that allows
areas of memory to be mapped to address 0x0000 0000. The default value of the shadow
pointer is 0x1040 0000, ensuring that the code contained in the boot ROM is executed at
reset.
For flash-based parts, the part boots from internal flash by default (boot pin P2_7 is
HIGH). If the boot pin is sampled LOW on reset, the boot source is determined by the
setting of the OTP or the states of pins P2_9, P2_8, P1_2, and P1_1. For details of the
boot process for flash-based parts, see
UM10503
Chapter 5: LPC43xx Boot ROM
Rev. 2.1 — 10 December 2015
User manual