We are developing one consumer system now. The concept is to divide single board concept in to two separate ones ( like SOM & Connectivity board).
SOM consists of i.MX6 dual lite+PMIC+Gigabit Ethernet PHY+BT/Wi-FI+eMMC+DDR3 and all other interface signals extended to a connector .
In this scenario we have the power supplies related to connectivity module and SOM input ( 3.3V) is generated in Connectivity board extended to SOM.
My questions here are with regards to Power and RESET.
1. Is it mandatory to have different 3.3V for PMIC input and Peripherals ? Like 3.3V and 3.3V# delayed supplies shown in one of the NXP Demo boards ( Sabre AI CPU Board - SCH-27767).?
Can we use a single 3V3 through out for PMIC as well as for Peripherals with out any control? Do you see any issue if the peripherals Powered up continuously before Processor Power ON?
2. Is there any specific RESET circuit preferred? I could see from NXP Demo boards that there are different RESET circuits used. A simple circuit used in Sabre SDB board is good enough to follow or do you suggest to use the one in Sabre AI CPU Board ( SCH-27767)?
3. Do external Watch dog timer is preferred to use like some of the partners demo boards like ( Anka by E-Con systems or Wandboard)?