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iMX28 BOOT_MODE bits in HW_OCOTP_ROM0, ROM Bootloader Codes

Question asked by Draghi Puterity on Sep 19, 2012
Latest reply on Oct 3, 2012 by PeterChan

Hello All,

 

I have the following problem: on the HW prototype I received for a new iMX28 board the LCD_RS was left open instead of being pulled high in order to boot as specified by the BM3-BM0 pins. Although LCD_RS ins not pulled low either, I assume the device is now booting as specified by the OTP. However the BOOT_MODE field (bits 24-31) are not documented in HW_OCOTP_ROM0 (20.4.7, page 1447 in iMX28 Application Processor Reference Manual, Rev. 1, 2010).

 

I want to boot from SSP0 from a SD card at 3.3V.

 

Can somebody document these bits? How are BM3-BM1, voltage selector and ETM enabler mapped on the BOOT_MODE field bits on the HW_OCOTP_ROM0? Are there also other relevant bits in this field I should be aware of? Learning by doing is clearly not an option for OTP

 

What are the codes the ROM bootloader is sending via the DEBUG UART (something like H0x80201005, etc) ?

 

Any help would be greatly appreciated.

 

Best regards,

 

Draghi Puterity

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