MangOH Red I2C Power Schematic Error?


#1

I’m trying to make sense of the I2C power supply in the schematic. I have two questions, both on Sheet 10:

  1. For the life of me, I can’t find a power supply that supplies VCC_I2C_M. Is there a jumper I’m missing?

  2. Related to #1, there’s a definite error on the schematic. R464 and R465 are zero-ohm resistors that connect VCC_1V8 and VCC_3V3 together as well as directly connecting them to VCC_I2C_M. At least one of those has to be a DNI or the board would catch fire, which it clearly doesn’t. So I’m wondering which (or neither?) is connected?


#2

There are two zero ohm resistors (R464, R465) on VCC_I2C_M power line to select either VCC_1V8 or VC_3V3.
By default R464 is populated for VCC_1v8. (as you see on schematics page 4, R465 is DNI and not populated).


#3

Huh, interesting. This schematic is slightly different than the one that I had been looking at. I wonder if I somehow have an older version or if not everything is being displayed correctly in MacOS’s “Preview” PDF viewer. The version I had didn’t have R465 marked as DNI.