LPC MicrocontrollersのトピックLPC54018JxM : IMG_BAUDRATE definition

LPC54018JxM : IMG_BAUDRATE definition

belmontbob59 — Fri, 17 May 2019 18:19:55 GMT

When running firmware directly from internal flash (XIP), the startup code defines the following for the image header for "spi_clock_freq" at offset 0x1C

IF :DEF: IMG_BAUDRATE
DCD IMG_BAUDRATE;(0x1C) image baudrate
ELSE
DCD 0 ; (0x1C) reserved
ENDIF

However, IMG_BAUDRATE is not defined anywhere in the SDK when compiling any example in XIP.

What is the value to set IMG_BAUDRATE when running in XIP mode for best performance ?

Thank you

Re: LPC54018JxM : IMG_BAUDRATE definition

jeremyzhou — Mon, 20 May 2019 02:23:18 GMT

Hi Bob,

Thank you for your interest in NXP Semiconductor products and
for the opportunity to serve you.
Actually, a good clock frequency is mainly determined by the QSPI flash chip you use.
Have a great day,
TIC

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Re: LPC54018JxM : IMG_BAUDRATE definition

belmontbob59 — Mon, 20 May 2019 15:50:43 GMT

LPC54018JxM does not have QSPI external flash chip, it has QSPI internal flash, chosen by NXP. What is the value to use for IMG_BAUDRATE for NXP's internal flash connected to

LPC54018JxM's QSPI for optimum performances ?

Re: LPC54018JxM : IMG_BAUDRATE definition

jeremyzhou — Tue, 21 May 2019 06:42:19 GMT

Hi Bob,

Thanks for your reply.
Q1) What is the value to use for IMG_BAUDRATE for NXP's internal flash connected to LPC54018JxM's QSPI for optimum performances?
-- It'd better not exceed the system clock frequency in the application code, meanwhile, close to the system clock.
Have a great day,
TIC

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