LPC4357JET256 nRESET doesn't work

[mike_phan]

Hello All

Does anyone know what is change in the two different version below ? Somehow I can't get the "nRESET" work in a newer version, but the older version working fine. Every time I press manual reset then the MCU hanging. Thank you for help

Newer Version:

-LPC4357JET256

-PBFV15.00

-ESD17160a

Older Version:

-LPC4357JET256

-PIXN23.00

-ESD15020A

[bernhardfink]

Don't see a lot of reasons for such an issue, both devices are the same silicon version 'A', one produced in week 02/2015 and the other one in week 16/2017.

Can you maybe read out the Boot ROM version on both devices?

Is it just one new device where it doesn't work?

Regards,

Bernhard.

[mike_phan]

Thanks Bernard.

Can you show me how do you read out the Boot ROM version?

it happens to all chips with new date code ESD17160A.

[jeremyzhou]

Hi mike phan,

Flash Magic tool is able to read out the Boot ROM version when connecting the LPC4357 which is forced to enter ISP mode.

You can learn how to do it via the following link.
https://learn.adafruit.com/getting-started-with-the-lpc810/programming-the-lpc810-with-flash-magic
Have a great day,
TIC

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[bernhardfink]

Hello Mike,

the rerason why I'm asking for the ROM version:  there is a problem like this under certain conditions on the old silicon version which is marked with '-'. See in this thread:  LPC1857- Revision changes 'A' vs '-'- Impact on sleep and reset.

This is a known bug.

I hope that the marking goes in line with the right silicon version in the package, but I can't exclude it.

So by reading the same ROM version number from both chips you mentioned, you would make sure that it is the same silicon and therefore we need to investigate in a different direction.

Regards,

Bernhard.