We understand that the sequence of power supply is below.
I.MX6ULL data sheet (IMX6ULLCEC 4.2)
· VDD_SNVS_IN -> VDD_HIGH_IN -> VDD_SOC_IN -> NVCC - xxx
· VDD_SOC_IN -> VDD_HIGH_IN -> VDD_SNVS_IN
By the way, it seems that the sequence of the evaluation board does not conform to the above specifications, is it good?
• VDD_SOC_IN -> NVCC_xxx
The 3.3 V system of NVCC is simultaneously with VDD_HIGH_IN, and VDD_SOC_IN is turned on after that.
· VDD_SOC_IN -> VDD_HIGH_IN
It is dropping at the same time by discharge.