In my project I use iMX287 as the MCU, and an external watchdog chip connected to the RESETN pin of the iMX287, but I found sometimes the RESETN pin can't reset the iMX287 successfully, and in this condition the iMX287 will continuously ‘died’ until turn off the 5V power and turn on it. In this 'died' condition, I found the VDDIO drop down to 3.1~3.2V, VDDD drop down to 1.2V and VDDA drop down to 1.0~1.1V. This happened immediately when the RESETN drop down to 0V. I use the official power_prep.c and patch it by L2.6.35_10.12_SDK_5V_SUPPLY_PATCH.
I don't know why this happened, and I also don't know in which condition this will happen. How can I solve this problem?