I set the boot device to NOR(EIM), but it dose not start.

[tamotsu]

This is a custom board using iMX7D.

I set BOOT_MODE to 0b10 and BOOT_CFG[15:0] to 0b0101010000111111, but when I turn on the power, /CE of NOR flash remains ay LOW level.

Thank you.

[Dhruvit]

Hi @tamotsu,

I hope you are doing well.

Please make sure that the boot image is correct & flashed succesfully.

Chip selects in EIM are active low.

Thanks & Regards,
Dhruvit Vasavada

[tamotsu]

Thank you Dhruvit.

I referred to SABRE's circuit diagram, but I also found that EIM's CS did not have pull-up register, so I added 10K registers.

But the result was the same.

How many seconds dose it take for the ROM to read BOOT_MD and BOOT_CFG after the MPU's POR_B start up?

It takes 3.3 mSec for BOOT_CFG start up after MPU POR_B start up.

Best regards.

[tamotsu · Accepted solution]

The BOOT_CFG resistor is pulled up to NVCC_3V3, but since NVCC_3V3 goes HI after POR_B goes HI, it is likely that the CFG information was not loaded into the ROM.

By changing the pull-up power supply of the BOOT_CFG resistor, the pull-up resistor of NOR (EIM)'s CE, and VDD to another power supply, we were able to confirm access to the CE of NOR (EIM) from the ROM. The cause is probably that the current of the NVCC_3V3 power supply was too large.

Best regards.