IMX6SOLO initial power up boot up issue

[guslabao]

Hi,

We have a design that is using the MCIMX6S5DVM10AC device with PMIC MMPF0100F6AEP.  On initial power up, the system does not boot.  When the board is powered up, we issue a manual POR to the IMX6 and then the system boots up properly. Why do we need to issue a second POR to IMX6?

When the POR is extended to about 2sec relative to PMIC PWR_ON, the system is booting properly from initial power up.  Is this extended POR required for the proper system boot up?   What is the required time for the IMX6 POR  relative to the PMIC PWR_ON?   Any recommendation what else is causing the failed boot up on initial power up?

Thanks,

Gus

[guslabao]

HI Igor,

I tried the internal ring oscillator for RTC_XTALI by tying the pin to GND and leave RTC_XTALO floating to avoid slow start up.

It still exhibit the same problem.  I did look at the caps for the power rails and VDDARM_CAP, VDDSOC_CAP,VDDPU_CAP.  I do have 22uF bulk caps.

Let me know if you have any other recommendations I can try.

Thanks,

Gus

[igorpadykov]

Hi Gus

it may be useful to check waveforms VSNVS_IN/VDD_SNVS_CAP,

VDDHIGH_IN/VDDHIGH_CAP and test case with permanent

connection licell to MMPF0100 LICELL.

Best regards

igor

[guslabao]

Hi Igor,

For the RTC_XTALI, what kind of a start time up do you expect? I am seeing about 600ms from when VDD_VSNVS is up.

Thanks,

Gus

[igorpadykov]

Hi Gus

when POR is released all power supplies and clocks should

be stable and within specs defined by datasheet.

Regarding RTC_XTALI (I believe you mean ERR007926),

it is fixed in rev.1.3 silicon ("C").

Best regards

igor

[guslabao · Accepted solution]

Hi Igor,

Thanks for your help.  The current solution is to extend the POR to meet the RTC_XTAL stability.

Used the circuit, SPF-27962 p.20 (U41 POR Reset) MX6SX SABRESDB to extend delay.

Regards,

Gus

[guslabao]

Hi Igor,

I extended the POR to about 600ms to fix the initial boot up issue.  Now if I power cycle a short ON/OFF it does not boot up.

If I extend POR further to about 1.5sec then the ON/OFF problem goes away, but the initial boot up issue comes back.

I am using the MCIMX6S5DVM10AC device with PMIC MMPF0100F6AEP.  What power up and down sequence do I need to follow for the SOLO device?

Does the preconfigured PMIC F6 version ok with the SOLO device power up sequence?

Thanks,

Gus

[santhakumara]

Hi Gus,

Could you share PMIC section of your schematic..

i hope i can answer this question since we also have faced this issue and got it resolved. it could be design error.

regards,

santhakumar.

[guslabao]

Hi Santhakumar,

I found the error on the PMIC section.

Thanks,

Gus

[pradeepn]

Can you please share the pmic design we also facing same boot up issue . OR tell us what was the error

[igorpadykov]

Hi Gus

please look at sect.4.2.1 Power-Up Sequence i.MX6SDL Datasheet (rev.5, 6/2015)

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6SDLCEC.pdf

~igor

[igorpadykov]

Hi Gus

issue may be related to long crystal start-up times, for example full 32KHz

start-up can be as much as 1 second. One can try solution used in

SPF-27962 p.20 (U41 POR Reset) MX6SX SABRESDB :

Schematics (2)

IMX6SOLOX-SABRESDB-DESIGNFILES

SABRE Board Reference Design|NXP

Best regards

igor

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[guslabao]

HI Igor,

I tried to the POR reset you suggested, extended it to about 1.15sec.  I still see a problem of not booting from eMMC on initial power up.  If I power cycle quickly, it seems to boot.  My guess, something is up and stable due to caps.

In terms of power sequencing, Do you see any issue using the PMIC MMPF0100F6AEP for the IMX6SOLO version? 

For the power sequencing of the IMX6SOLO, is there any special sequencing that need to happen first?

Thanks,

Gus

[guslabao]

Hi Igor,

I have extended the POR to 2sec and it seems to boot from eMMC on initial power up.  Is this a requirement for IMX6SOLO to have such a long POR?

I just find that a 2 second delay is a long time.  Let me know if there are other recommendation that we can try that does not involve have to add this delay.

Thanks,

Gus

[igorpadykov]

Hi Gus

IMX6SOLO has not requirements for such a long POR, seems this is due

to board design, in particular crystal long start-up times.

Recommendation for not adding this delay, is to use verfied

designs with i.MX6Solo - Sabre schematic on

spf-27392,SPF-27516

"iMX6_SABRE_SDB_DESIGNFILES  : Design files"

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=RDIMX6SABREBRD&fpsp=1&tab=Design_Tool...

Best regards

igor

[guslabao]

Hi Igor,

I can seem to find the spf-27392 schematic.  Can you direct me to location.

So what you are saying is that I should be using the exact crystal on the design?

thanks,

Gus

[igorpadykov]

Hi Gus

I am afraid that reference design i.MX6S with PMIC MMPF0100F6AEP

is not available. So recommendation just follow spf-27392 schematic.

Regarding design with "F6", recommended to recheck below link,

in particular capacitor requirements

HW Design Checking List for i.MX6DQSDL

Best regards

igor