topic Re: Retention of the flash for Erase command in LPC Microcontrollers

Retention of the flash for Erase command

ranjithshanbhag — Thu, 26 Apr 2018 12:51:35 GMT

In LPC824 last page is used as Emulated EEPROM. Found during firmware update through Flash Magic with CRP = 1 or CRP = 2, found Emulated EEPROM also getting erased. Please suggest me how prevent this?

In Emulated EEPROM is used to save critical data and want to retain during Firmware Upgrade.

Re: Retention of the flash for Erase command

jeremyzhou — Fri, 27 Apr 2018 01:38:32 GMT

Hi Ranjith Shanbhag，

Thank you for your interest in NXP Semiconductor products and

the opportunity to serve you.

I'm afraid partial flash pages would be affected after execute erase commands for particular sector which contains these pages.

It's no way to avoid this affection.

TIC

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Re: Retention of the flash for Erase command

ranjithshanbhag — Fri, 27 Apr 2018 08:25:10 GMT

Thanks jeremyzhou for our quick reply.

I understand, Emulated EEPROM is sitting in last page, erasing this page can be prevented with above mentioned setting?

Re: Retention of the flash for Erase command

jeremyzhou — Sat, 28 Apr 2018 04:56:23 GMT

Hi Ranjith Shanbhag

Thanks for your reply.

Sorry, I'm not clear with the meaning of "Emulated EEPROM is sitting in last page, erasing this page can be prevented with above mentioned setting?" Whether you can clarify it.

TIC

Re: Retention of the flash for Erase command

ranjithshanbhag — Mon, 30 Apr 2018 05:09:45 GMT

Hi Jeremy,

Last page of the Flash is configured as EEPROM, During Firmware upgrade with above mentioned setting whether erasing can be prevented?

Re: Retention of the flash for Erase command

jeremyzhou — Wed, 02 May 2018 02:38:23 GMT

Hi Ranjith Shanbhag,

Thanks for your reply.

1) During Firmware upgrade with above mentioned setting whether erasing can be prevented?

No, I'm afraid not.

TIC

Re: Retention of the flash for Erase command

hparracho — Wed, 02 May 2018 13:08:59 GMT

I guess you can only do what you want if your firmware doesn't use the entire last sector of flash memory. If that's the case, select the option to only "erase blocks used by firmware" in flashmagic.

If it's not the case, unless you have a bootloader able to read the last page prior to update firmware and then restore it, I don't see how you can preserve only the last page of your flash.

Re: Retention of the flash for Erase command

ranjithshanbhag — Wed, 02 May 2018 14:11:36 GMT

Hi Jeremy,

Thanks for your reply.

i convinced with your response.

With CRP1 or CRP2 setting, if we design a GUI for firmware upgrade by using ISP commands, whether it is possible to erase required sectors? Ultimate goal is EEPROM has to be retained which is there in last page.