Hi,
Can someone please confirm this for me:
1) I just spun a board with a SOM OMAP138, and I left the IO_VOLT_SEL pin floating, so that the IO signals are 3.3V.
2) I then have some ICs (RS485 transceivers, external SRAM) on my custom baseboard that are powered by a different +3.3V (which share the same digital ground as the SOM).
The question is that even though both the SOM’s IO signals and the external circuitry’s IO signals are at +3.3V, do I still need the “dual rail” level shifters (similar to the SN74AVC16T245DGG used on the LogicPD’s baseboard) to eliminate power sequencing (I.e. Ioff) issues? For example, I would assume that if the +3.3V on the SOM came up first, that there would be a possible latch-up condition do the parasitic diodes in the external circuitry going to a rail which is less than the SOM’s +3.3V. Or, vise-versa…

Thanks.