Clarifications on expansion board connector

Hi all,

Following on from the board meeting presentation by Daniel, I wanted to double check the expansion board connector choice.

Just to summarise the discussion:

• it would have been good to use an FMC connector but the power requirements of an OCXO prevent this (limited current on 12V rail)
• it makes sense to go to a right-angle connector to enable push-to-mate connections
• Samtec make a similar connector that won't cost too much more

The two mating connectors chose are:

• SEAF-50-01-L-08-2-RA-GP-TR
• SEAM-50-01-L-08-2-RA-GP-K-TR

A couple of notes:

• the FMC standard has two variants, Low Pin Count (LPC) and High Pin Count (HPC)
• both variants use the same connector, just with rows fully populated for the HPC variant
• the connector is 10 rows x 40 pins

The Samtec SEAM/SEAF range supports a number of row x column variants, one of which is a 10 row x 40-pin that would match the FMC standard more closely. Would this be a better choice than the 50-pin variant? It seems to me that we could use the LPC pinout for boards that fitted within the 12V 1A power budget and then use extra pins of the HPC connector for power when needed. Assuming we don't need the extra IO of the HPC.

The downside to using the 50-pin variant is that there is no standard pinout as far as I can tell. Was the intent to define a new pinout specific to the WRSv4?

Additionally, is it an option to use the SEARAY UBPT/UBPS power modules for those who need extra power? It could even be an optional fit/switch variant.