Boot i.mX 1050

[christiangradl]

Hi,

i set GPIO_AD_B0_04-BOOT_MODE0 to HIGH and GPIO_AD_B0_05-BOOT_MODE1  to LOW

=> boot mode "Serial Downloader"

But when i put a high signal on GPIO_AD_B1_11 or on GPIO_B1_13 then the Serial Downloader does not start.

A low signal on or open the downloader mode starts

Are there any undocumented functions?

[CarlosCasillas]

Hi Christian,

The Serial Downloader could be accessed by USB/LPUART. You could refer to Figure 8-1 “Boot flow” of the i.MX RT1050 Reference Manual for details regarding the proper boot sequence to enter in Serial Downloader mode.

Hope this will be useful for you.
Best regards!
/Carlos
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[christiangradl]

I connected GPIO_B0_05 with 3v3. Then i pressed the POR Button and the i.mx RT1052 is ruined and gets very hot. My EVK board is now defect. I tested the same with another EVK board, same thing. Whats going wrong here? I think there is a bug in the i.mx?

[art]

Hello Christian,

The possible reason of the fact that the processor becomes damaged on the second board after pressing the POR button is as follows. Here I call "first" the board that is connected to the USB Host bus through the OpenSDA connector and distributes power and GPIO signals to the "second" board.

Please refer to the Sheet 4 of the i.MX RT1050 EVK board schematic. As it can be seen, pressing the SW3 POR button switches off the U3 DCDC converter, that produces the DCDC_3V3 voltage, that is the main system power supply voltage. Thus, pressing and releasing the SW3 button completely power cycles the board.

So, when you press and hold the SW3 button, the board power is completely switched off, including the GPIO power banks. At the same time, the 3.3V supply voltage from the first board is directly (even without any current limiting resistors) is applied to some GPIOs of the second board's processor. In this situation, the GPIO circuits of the second board's processor become irreversibly damaged.

Also, applying the supply voltage directly to the GPIO pins is not a good practice. Some series current limiting resistors (at least of 1kOhm) should be used in that case.

Best Regards,
Artur

[christiangradl]

This answer does not help.

i am using the EVK board. I set all switched, etc. correct for booting in Serial Bootloader Mode

If pin GPIO_AD_B1_11 is pulled up to 3v3 from an external source (2nd processor) the Serial Bootloader Mode does not start.

I tested this strange behaviour on serveral EVK boards.

POR or reset does not help in this situation, i have no idea why. The only thing i see is, that i.mx samples a wrong bootmode on the rising edge of POR_B.

The POR_B signal is not correct when GPIO_AD_B1_11 is pulled up to 3v3 from an external source.