Question, i.MX28 EVK boot

[Aemj]

Dear team,

I would like ask about the boot behavior of i.MX28-EVK.

Mu customer is trying to boot from SD card on your i.MX28 EVK board, and they saw the following phenomenon.

The boot goes to serial download mode even when SD-Card is inserted.

The procedure is as below;

(1)

When they set S2 switch to “1001”, and they verified SD boot operation succeeded.

(2)

After removing AC power supply from EVK, connect J82(USB-OTG port) to PC.

(3)

When they attached AC power supply to EVK, the boot seemed to go into serial download mode. Some characters seemed to be flowed out from USB port periodically.

And when they pushed POWER sw of EVK in the above situation, then SD boot started.

I think the right behavior of boot is;

Starting SD boot when S2 SW setting is set to SD card boot after power on even if USB port is connected to PC.

Correct?

I think the normal POR reset of i.MX28 cannot be done by only the insertion of AC adapter to EVK. It may need to push POWER SW.

Please give your comment about the workaround of this issue.

Thanks,

Miyamoto

[Yuri]

Hello,

 Basically i.MX28 supports two power on options :

- rising supply voltage on VDD5V ;

- PSWITCH assertion, when DCDC_BATT is proper and stable.

Note1 : on the EVK VDD5V may be provided by USB or by external 5V source,

depending on S16 switch.

Note2 : USB activity may be performed by i.MX28 boot ROM, if USB cable

is plugged.

You are right, that SD boot starts, when S2 SW setting is set to SD card boot
after power on even if USB port is connected to PC.

Have a great day,
Yuri

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