Port E Bit 4 is not on the PCIe connector on RCM6750.

Question

PE4 appears to be disconnected in the 6700 schematics. It does not go out to the PCIe connector like all the other Port E bits.

Can it be accessed if ethernet is not required on an RCM6750 module?

Answer 1

Looking at the schematic, it doesn't appear to physically go anywhere at all, not even to a test point. I'm sure you could write code to configure it as an input or output, but how would you connect something to it?

Since PE4 is used as on-board I/O for other Minicore modules, it wasn't included in the PCIe pinout. To remain compatible with the other products, the RCM67xx modules don't make use of it either.

Is there something you can do with PE4 that you can't do with one of the other I/O pins on the PCIe connector?

Answer 2

I want to update an old application for the RCM4120. PE4 was available on that module. The application uses all available pins on that module so I do need all of port E to match it.

Comments

If the RCM6700 doesn't provide enough I/O, you'll have to look at using additional hardware in your board design to get the full number of pins required.  If you were using port E as a parallel port, you'll have to look into using another port where all 8 bits are available for use.