How do I choose my Power I/O Voltages
Following the AM335x Hardware Design Guide, I’m working with the Pin Mux Utility to design my board. I’m not sure how to choose my Voltages for my I/O Power Voltages (VDDSHV1-VDDSHV6).
Do I choose these voltages based on the voltages of the peripherals I connect to my board? Is there any information regarding this process?
VDDSHV1 (GPMC)—I assume I set this at 1.8V if I’m using 1.8V Memory and 3.3V if I’m using 3.3, is that right?
MMCSD-B and A—I’m not sure why there’s a B and an A. I assume that since I plan to place a SD Card Reader on the board I should choose this based on the logic voltages for my attached chip(s). Is that right?
GEMAC A and B—What is this? I assume it’s Ethernet. Why are there two?
General—I assume this governs all my other peripherals, i.e. I plan to a UART, CAN and USB. Do I choose this voltage based on the logic voltages to these devices?
I spent a few hours looking through the Forums, the Data Sheets, Users Guide and Technical Reference Manual and couldn’t find any information. I feel like I must be asking a really stupid and remedial question, but I’ve never worked on a processor that allows for multiple supply rails. I really appreciate any help. Thank you so very much.