PSoC5LP GPIO initial state change (NVL)

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PSoC5LP GPIO initial state change (NVL)

MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored
‎Jul 07, 2019 06:38 PM
‎Jul 07, 2019 06:38 PM
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Hi,

We would like to confirm the rewriting of NVL.

It is necessary to set GPIO low after POR.

Therefore, We set the reset tab of Configure 'Pin' to "Pulled-Down" and wrote the program.

GPIO goes low after POR as expected.

We know that NVL has a rewrite endurance value.

Endurance of Non-volatile Latches (NVL) in PSoC 3/5

In order not to rewrite the information of the NVL set in the pull-down,
When overwriting, it was set the reset tab of Cofigure 'Pin' to "Don't Care".

Operation was confirmed after setting to "Don't Care".
Then it looks like the pin is set to Hi-Z. Not Low.

Should we always write with the Configure 'Pin' settings "Pulled-Down"?

If it is necessary to always write using "Pull-Down" settings, does the rewrite endurance value always decrease every time?

We were aware that the "Don't Care" setting did not rewrite the NVL information, but it seems to be different when we confirm for the pin operation.

Regards,

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Re: PSoC5LP GPIO initial state change (NVL)

Takashi_M
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1000 replies posted 500 solutions authored 750 replies posted
‎Jul 10, 2019 07:11 PM
‎Jul 10, 2019 07:11 PM
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According to PSoC 5LP Device Programming Specification the NVL in device will be rewritten, only when the NVL content is different from the one stored in device and the one in HEX file.

That mean NVL rewriting happens by any changing NVL content, i.e pin Power-On Reset configuration changed “Don’t care” to “Pulled-Down”, and “Pulled-Down” to “Don’t care”.

And if you doesn’t change pin Power-On Reset confirmation, NVL content is same in device and HEX file. In this case, NVL rewriting doesn’t occur.

Therefore,

> Should we always write with the Configure 'Pin' settings "Pulled-Down"?

Yes, if you decide to set “Pulled-Down” for pin, it would be better to keep same “Pulled-Down” configuration for that pin from NVL endurance perspective

> If it is necessary to always write using "Pull-Down" settings, does the rewrite endurance value always decrease every time?

No, this is because NVL rewriting occurs only when NVL content is different between in device and in HEX file.

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