LPC Microcontrollers中的主题 Rated clock speed for single cycle flash access on LPC11E6x

Rated clock speed for single cycle flash access on LPC11E6x

jamesl-dm — Tue, 08 May 2018 08:34:40 GMT

I'm using an LPC11E67JBD48, and can't find a specification for the flash access speed in either the datasheet or the user manual. After POR, the FLASHCFG->FLASHTIM register reads back as 0xC002, which does not match the user manual's register description.

The manual says that the lower two bits correspond to:

0x0 1 system clock flash access time.
0x1 2 system clocks flash access time. (default - according to the manual)
0x2 Reserved. (what my chip is actually reporting)
0x3 Reserved.

I've tried lowering the FLASHTIM register from 2 to 0, and this definitely results in a speed boost at 16 MHz, so the default value is more than 1 clock cycle.

So my question is, what is the maximum clock speed that I can use at each setting of FLASHTIM? I want to run the flash as fast as possible on my 16 MHz clock, without the risk of flash corruption at temperature / voltage extremes. Usually this information is available in the datasheet.

Re: Rated clock speed for single cycle flash access on LPC11E6x

jeremyzhou — Wed, 09 May 2018 02:25:33 GMT

Hi jamesl-dm,

Thank you for your interest in NXP Semiconductor products and

the opportunity to serve you.

Please checking the Fig 1 which illustrates a variety of flash access time.

Have a great day,
TIC

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Re: Rated clock speed for single cycle flash access on LPC11E6x

jamesl-dm — Wed, 09 May 2018 03:52:10 GMT

Thanks Jeremy! I guess the datasheets that ship with the Keil software pack are out of date... I should have realized and checked the website for an update.