Dear All,
Hello.
I have a question about Boot mode sampling timing in i.MX6DQ.
I found the below 3 descriptions.
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1. Refer to the 60.6.1.2.3 POR (SRC_POR_B) in IMX6DQRM(Rev.2) - page.5056.
"Once the above resets deassert, system_early_rst_b reset is deasserted after 2 XTALI clocks."
2. Refer to 60.6.1.2.4 COLD RESET in IMX6DQRM(Rev.2) - page.5056.
"Once the reset source deasserts, system_early_rst_b reset is deasserted after at least 2 XTALI clocks."
3. Refer to the 59.4.4.1 BMOD Pin Latching in IMX6DQRM(Rev.0) - page.5008.
"All the boot pins will be sampled at deassertion of system_early_rst_b."
========
So, I understood that All the boot pins will be sampled after at least 2 XTALI clocks from POR_B.
[Question]
How much is it necessary to keep the logic of Boot Mode Configuration Pins?
(Best case : 2XTALI clocks. Worst case : ?? clocks)
Best Regards,
Keita
Solved! Go to Solution.
The boot pins are latched at POR rising edge, but - strictly speaking -
the hold time is not specified. Please look at sheet 13 of the i.MX6 SL EVK
design, where bus isolation buffer is applied and the next note is provided :
"i.MX6SL reads values approximately 300uS to 1mS after reset released.
Buffers are active while unit is in reset and 1ms-10ms after reset is released."
Have a great day,
Yuri
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Hi Yuri,
Thank you for your reply.
[Q1]
Can this description be adaptable to i.MX6DQ, too?
[Q2]
What meaning of "unit is in reset"?
[Q3]
Should I keep the logic of Boot Mode Configuration Pins more long than at least 1 mS after reset released?
Best regards,
Keita
Please look at my comments below.
1.
> Can this description be adaptable to i.MX6DQ, too?
Yes - in order to be fully on safeside.
2.
> What meaning of "unit is in reset"?
While POR is asserted.
3.
> Should I keep the logic of Boot Mode Configuration Pins more long than
> at least 1 mS after reset released?
I do not think so.
Regards,
Yuri.
Hi Yuri,
Thank you for your reply.
Sorry. I couldn't understand well about below answer #3.
>3.
>> Should I keep the logic of Boot Mode Configuration Pins more long than
>> at least 1 mS after reset released?
>I do not think so.
I send you the below question again.
How long does it necessary to keep the logic of Boot Mode Configuration Pins after reset released?
Best Regards,
Keita
The value of 1.1 ms is good.
Regartds,
Yuri.
Hi Yuri,
Thank you for your reply.
OK. I got it.
Best Regards,
Keita