Drive state unknown during reset in i.MX6DQ.

[keitanagashima]

Dear Sir or Madam,

Hello.

Refer to "Table 101. Signals with Differing Before Reset and After Reset States" in IMX6DQAEC(Rev.3)

GPIO_17, GPIO_19 and, KEY_COL0 Values are "Drive state unknown ( x )".

Q1.

What is the meaning of "Drive state unknown ( x )"?

Q2.

My customer would like to fix the Hi or Lo only during reset.

Do you have any solution ? (Add external schematic? or Set by software?)

Best Regards,

Keita

[igorpadykov · Accepted solution]

Hi Keita

meaning of "Drive state unknown is that value

may be random state (it is not initialized internally by processor).

Seems as external schematic is solution, since

it can not be set by software, because software can be run

only after processor reset. Table 100 shows state immediately

after reset, Table 101 - before reset.

Best regards

igor

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[keitanagashima]

Hi Igor,

My customer tried to pull-down by 2.2k ohm for GPIO_19.

But, it remained about 2V.

So, could you tell me the drive ability in case of the Before Reset State condition?

Best Regards,

Keita

[igorpadykov]

Hi Keita

suggest not to use pull resistors,

try tri-state circuit, so i.MX6 pad

was fully isolated from external chip.

~igor

[keitanagashima]

Hi Igor,

Thank you for your special support.

OK. I got it.

Best Regards,

Keita