FPGA no-connects for 45 size FPGA on MityDSP-L138F
Added by Thomas Catalino over 12 years ago
(Posted on behalf of a customer)
We have done a design using the MityDSP-L138F SOM. I tried avoiding using the pins on the FPGA that are not connected in the larger variant, but I was not succesfull, meaning I accidently used two of the pins, namely 170 + 172 (FPGA pins E7 + E8); which is fine for the -16 variant of the FPGA.
For our prototypes we would like to be able to use the -45 variant of the FPGA and hence my question:
How are SOM pins 170 + 172 on the -45 (L138-xI-225-Rx) connected?
If they are floating I can do a "hack" on the SOM, which would provide the most "elegant" fix to my bug.
Replies (2)
RE: FPGA no-connects for 45 size FPGA on MityDSP-L138F - Added by Michael Williamson over 12 years ago
The bare board PCB for the two variants of the SOM are identical, the only difference is the BOM used for assembly. Pins 170 and 172 are still routed to the balls on the FPGA (E7/E8). However, I'm fairly certain that these pins are not bonded on the LX45 (you'll need to check with the Xilinx datasheets to confirm this), and they are effectively floating. It's probably worth a try to implement your "hack".
-Mike
RE: FPGA no-connects for 45 size FPGA on MityDSP-L138F - Added by Anders Joergensen over 12 years ago
I've tried out the "hack" and it works fine; so yes indeed they are floating.
-anders
