I.MX6Q first boot fail!

[tommyduan]

• Cars have ACC and B +,We find that now ACC and B+ are both up, causing the CPU to fail to start;If B+ is turned on continuously and only ACC is disconnected,When I'm only on ACC,it will start up normally;The main difference between the two is only breaking ACC, RTC electricity is always available;Do not understand the main impact of CPU start up?This is still a probabilistic question, and I can work if I change the CPU.If there is a problem, I delay the CPU reset time, which can reduce the probability, but cannot be completely solved!

• Sometimes the power cut takes too long to start,Sometimes breaking 10S can be redone!Can you provide a possible reason, or we can test and verify the method, thank you!

[igorpadykov]

Hi tommy

may be recommended first to rerun ddr test and update uboot with new

calibration coefficients

https://community.nxp.com/docs/DOC-105652 

If this will not help check power-up sequence, use Hardware Guide document for used

processor, pay attention for clocks stability and power supplies. Note that no powered

devices are allowed to be connected to i.MX processor before its power-up (this is requirement of

power-up sequence).

Best regards
igor
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[tommyduan]

I do ddr stress testing,it's ok!I didn't find anything unusual on power up sequence.We need to focus on which electrical timing. And what we need to focus on which Crystal oscillator?The role of 32.768K crystal vibration in the process of power-up?What is the requirement of this crystal vibration?There is no other way to verify that the system is not up.