i.MX6 SoloX POR_B pin behaviour

[andrewbushuev]

Hello All,

We have a custom board based on i.MX6 SoloX and we are running Linux on it.
We have encounterd undocumented POR_B pin behaviour.

In particularly, NXP specifies the minimum duration of the input POR_B signal as 30.5 us (1 RTC_XTALI cycle).
However, from practical experiments (using our board), a shorter pulse (shorter than 1 us) on the POR_B input resets the processor.
We didn't find any references to the issue in the "Chip Errata for the i.MX 6SoloX" (Rev. 1, 04/2016).

Can somebody help us to know why is this so?

[igorpadykov]

Hi Andrew

datasheet specifies minimum duration for worst case, in all PVT corners,

that is for all variations in process technology and temperature&voltage ranges.

Best regards
igor
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[andrewbushuev]

Igor,

Please review the attachment ("i.MX 6SoloX Applications Processors for Industrial Products - Data Sheet (REV 2)")

By the datasheet Duration of POR_B should be greater than 1 RTC_XTALI cycle,

Yes, indeed, the datasheet specifies minimum duration for worst case, but in our case we can reset the CPU by a shorter pulse (less than 1 RTC_XTALI cycle).

[igorpadykov]

Datasheet describes guaranteed duration of POR_B (for all possible conditions),

but less durations also may reset cpu, however they are not guaranteed for

all conditions.

~igor